git.exc.InvalidGitRepositoryError when running finetune_rag.py
## Environment info
```
- `transformers` version: 4.10.0
- Platform: Linux-5.4.104+-x86_64-with-Ubuntu-18.04-bionic
- Python version: 3.7.11
- PyTorch version (GPU?): 1.9.0+cu102 (True)
- Tensorflow version (GPU?): 2.6.0 (True)
- Flax version (CPU?/GPU?/TPU?): not installed (NA)
- Jax version: not installed
- JaxLib version: not installed
- Using GPU in script?: Yes
- Using distributed or parallel set-up in script?: No
```
I'm on Colab.

### Who can help
research_projects/rag: @patrickvonplaten, @lhoestq

## To reproduce

Steps to reproduce the behavior:

1. 
```
!python transformers/examples/research_projects/rag/consolidate_rag_checkpoint.py \
    --model_type rag_token \
    --generator_name_or_path facebook/mbart-large-cc25 \
    --question_encoder_name_or_path voidful/dpr-question_encoder-bert-base-multilingual \
    --dest /content/checkpoint
```
2.
```
!python transformers/examples/research_projects/rag/finetune_rag.py \
    --data_dir /content/transformers/examples/research_projects/rag-end2end-retriever/test_run/dummy-train-data \
    --output_dir /content/finetune_output \
    --model_name_or_path /content/checkpoint \
    --model_type rag_token \
    --fp16 \
    --use_dummy_dataset True
```
# Error
```
loading configuration file /content/checkpoint/config.json
Model config RagConfig {
  "architectures": [
    "RagTokenForGeneration"
  ],
  "dataset": "wiki_dpr",
  "dataset_split": "train",
  "do_deduplication": true,
  "do_marginalize": false,
  "doc_sep": " // ",
  "exclude_bos_score": false,
  "forced_eos_token_id": 2,
  "generator": {
    "_name_or_path": "",
    "_num_labels": 3,
    "activation_dropout": 0.0,
    "activation_function": "gelu",
    "add_bias_logits": false,
    "add_cross_attention": false,
    "add_final_layer_norm": true,
    "architectures": [
      "MBartForConditionalGeneration"
    ],
    "attention_dropout": 0.0,
    "bad_words_ids": null,
    "bos_token_id": 0,
    "chunk_size_feed_forward": 0,
    "classif_dropout": 0.0,
    "classifier_dropout": 0.0,
    "d_model": 1024,
    "decoder_attention_heads": 16,
    "decoder_ffn_dim": 4096,
    "decoder_layerdrop": 0.0,
    "decoder_layers": 12,
    "decoder_start_token_id": null,
    "diversity_penalty": 0.0,
    "do_sample": false,
    "dropout": 0.1,
    "early_stopping": false,
    "encoder_attention_heads": 16,
    "encoder_ffn_dim": 4096,
    "encoder_layerdrop": 0.0,
    "encoder_layers": 12,
    "encoder_no_repeat_ngram_size": 0,
    "eos_token_id": 2,
    "finetuning_task": null,
    "forced_bos_token_id": null,
    "forced_eos_token_id": 2,
    "gradient_checkpointing": false,
    "id2label": {
      "0": "LABEL_0",
      "1": "LABEL_1",
      "2": "LABEL_2"
    },
    "init_std": 0.02,
    "is_decoder": false,
    "is_encoder_decoder": true,
    "label2id": {
      "LABEL_0": 0,
      "LABEL_1": 1,
      "LABEL_2": 2
    },
    "length_penalty": 1.0,
    "max_length": 1024,
    "max_position_embeddings": 1024,
    "min_length": 0,
    "model_type": "mbart",
    "no_repeat_ngram_size": 0,
    "normalize_before": true,
    "normalize_embedding": true,
    "num_beam_groups": 1,
    "num_beams": 5,
    "num_hidden_layers": 12,
    "num_return_sequences": 1,
    "output_attentions": false,
    "output_hidden_states": false,
    "output_past": true,
    "output_scores": false,
    "pad_token_id": 1,
    "prefix": null,
    "problem_type": null,
    "pruned_heads": {},
    "remove_invalid_values": false,
    "repetition_penalty": 1.0,
    "return_dict": true,
    "return_dict_in_generate": false,
    "scale_embedding": true,
    "sep_token_id": null,
    "static_position_embeddings": false,
    "task_specific_params": {
      "translation_en_to_ro": {
        "decoder_start_token_id": 250020
      }
    },
    "temperature": 1.0,
    "tie_encoder_decoder": false,
    "tie_word_embeddings": true,
    "tokenizer_class": null,
    "top_k": 50,
    "top_p": 1.0,
    "torch_dtype": null,
    "torchscript": false,
    "transformers_version": "4.10.0",
    "use_bfloat16": false,
    "use_cache": true,
    "vocab_size": 250027
  },
  "index_name": "exact",
  "index_path": null,
  "is_encoder_decoder": true,
  "label_smoothing": 0.0,
  "max_combined_length": 300,
  "model_type": "rag",
  "n_docs": 5,
  "output_retrieved": false,
  "passages_path": null,
  "question_encoder": {
    "_name_or_path": "",
    "add_cross_attention": false,
    "architectures": [
      "DPRQuestionEncoder"
    ],
    "attention_probs_dropout_prob": 0.1,
    "bad_words_ids": null,
    "bos_token_id": null,
    "chunk_size_feed_forward": 0,
    "decoder_start_token_id": null,
    "diversity_penalty": 0.0,
    "do_sample": false,
    "early_stopping": false,
    "encoder_no_repeat_ngram_size": 0,
    "eos_token_id": null,
    "finetuning_task": null,
    "forced_bos_token_id": null,
    "forced_eos_token_id": null,
    "gradient_checkpointing": false,
    "hidden_act": "gelu",
    "hidden_dropout_prob": 0.1,
    "hidden_size": 768,
    "id2label": {
      "0": "LABEL_0",
      "1": "LABEL_1"
    },
    "initializer_range": 0.02,
    "intermediate_size": 3072,
    "is_decoder": false,
    "is_encoder_decoder": false,
    "label2id": {
      "LABEL_0": 0,
      "LABEL_1": 1
    },
    "language": "multilingual",
    "layer_norm_eps": 1e-12,
    "length_penalty": 1.0,
    "max_length": 20,
    "max_position_embeddings": 512,
    "min_length": 0,
    "model_type": "dpr",
    "name": "DPRQuestionEncoder",
    "no_repeat_ngram_size": 0,
    "num_attention_heads": 12,
    "num_beam_groups": 1,
    "num_beams": 1,
    "num_hidden_layers": 12,
    "num_return_sequences": 1,
    "output_attentions": false,
    "output_hidden_states": false,
    "output_scores": false,
    "pad_token_id": 0,
    "position_embedding_type": "absolute",
    "prefix": null,
    "problem_type": null,
    "projection_dim": 0,
    "pruned_heads": {},
    "remove_invalid_values": false,
    "repetition_penalty": 1.0,
    "return_dict": true,
    "return_dict_in_generate": false,
    "revision": null,
    "sep_token_id": null,
    "task_specific_params": null,
    "temperature": 1.0,
    "tie_encoder_decoder": false,
    "tie_word_embeddings": true,
    "tokenizer_class": null,
    "top_k": 50,
    "top_p": 1.0,
    "torch_dtype": null,
    "torchscript": false,
    "transformers_version": "4.10.0",
    "type_vocab_size": 2,
    "use_bfloat16": false,
    "vocab_size": 119547
  },
  "reduce_loss": false,
  "retrieval_batch_size": 8,
  "retrieval_vector_size": 768,
  "title_sep": " / ",
  "torch_dtype": "float32",
  "transformers_version": null,
  "use_cache": true,
  "use_dummy_dataset": false,
  "vocab_size": null
}

Could not locate the tokenizer configuration file, will try to use the model config instead.
Didn't find file /content/checkpoint/question_encoder_tokenizer/added_tokens.json. We won't load it.
loading file /content/checkpoint/question_encoder_tokenizer/vocab.txt
loading file /content/checkpoint/question_encoder_tokenizer/tokenizer.json
loading file None
loading file /content/checkpoint/question_encoder_tokenizer/special_tokens_map.json
loading file /content/checkpoint/question_encoder_tokenizer/tokenizer_config.json
Could not locate the tokenizer configuration file, will try to use the model config instead.
Didn't find file /content/checkpoint/generator_tokenizer/sentencepiece.bpe.model. We won't load it.
Didn't find file /content/checkpoint/generator_tokenizer/added_tokens.json. We won't load it.
loading file None
loading file /content/checkpoint/generator_tokenizer/tokenizer.json
loading file None
loading file /content/checkpoint/generator_tokenizer/special_tokens_map.json
loading file /content/checkpoint/generator_tokenizer/tokenizer_config.json
Assigning ['ar_AR', 'cs_CZ', 'de_DE', 'en_XX', 'es_XX', 'et_EE', 'fi_FI', 'fr_XX', 'gu_IN', 'hi_IN', 'it_IT', 'ja_XX', 'kk_KZ', 'ko_KR', 'lt_LT', 'lv_LV', 'my_MM', 'ne_NP', 'nl_XX', 'ro_RO', 'ru_RU', 'si_LK', 'tr_TR', 'vi_VN', 'zh_CN'] to the additional_special_tokens key of the tokenizer
Loading passages from wiki_dpr
WARNING:datasets.builder:Using custom data configuration dummy.psgs_w100.nq.no_index-dummy=True,with_index=False
WARNING:datasets.builder:Reusing dataset wiki_dpr (/root/.cache/huggingface/datasets/wiki_dpr/dummy.psgs_w100.nq.no_index-dummy=True,with_index=False/0.0.0/91b145e64f5bc8b55a7b3e9f730786ad6eb19cd5bc020e2e02cdf7d0cb9db9c1)
loading weights file /content/checkpoint/pytorch_model.bin
All model checkpoint weights were used when initializing RagTokenForGeneration.

All the weights of RagTokenForGeneration were initialized from the model checkpoint at /content/checkpoint.
If your task is similar to the task the model of the checkpoint was trained on, you can already use RagTokenForGeneration for predictions without further training.
loading configuration file /content/checkpoint/config.json
Model config RagConfig {
  "architectures": [
    "RagTokenForGeneration"
  ],
  "dataset": "wiki_dpr",
  "dataset_split": "train",
  "do_deduplication": true,
  "do_marginalize": false,
  "doc_sep": " // ",
  "exclude_bos_score": false,
  "forced_eos_token_id": 2,
  "generator": {
    "_name_or_path": "",
    "_num_labels": 3,
    "activation_dropout": 0.0,
    "activation_function": "gelu",
    "add_bias_logits": false,
    "add_cross_attention": false,
    "add_final_layer_norm": true,
    "architectures": [
      "MBartForConditionalGeneration"
    ],
    "attention_dropout": 0.0,
    "bad_words_ids": null,
    "bos_token_id": 0,
    "chunk_size_feed_forward": 0,
    "classif_dropout": 0.0,
    "classifier_dropout": 0.0,
    "d_model": 1024,
    "decoder_attention_heads": 16,
    "decoder_ffn_dim": 4096,
    "decoder_layerdrop": 0.0,
    "decoder_layers": 12,
    "decoder_start_token_id": null,
    "diversity_penalty": 0.0,
    "do_sample": false,
    "dropout": 0.1,
    "early_stopping": false,
    "encoder_attention_heads": 16,
    "encoder_ffn_dim": 4096,
    "encoder_layerdrop": 0.0,
    "encoder_layers": 12,
    "encoder_no_repeat_ngram_size": 0,
    "eos_token_id": 2,
    "finetuning_task": null,
    "forced_bos_token_id": null,
    "forced_eos_token_id": 2,
    "gradient_checkpointing": false,
    "id2label": {
      "0": "LABEL_0",
      "1": "LABEL_1",
      "2": "LABEL_2"
    },
    "init_std": 0.02,
    "is_decoder": false,
    "is_encoder_decoder": true,
    "label2id": {
      "LABEL_0": 0,
      "LABEL_1": 1,
      "LABEL_2": 2
    },
    "length_penalty": 1.0,
    "max_length": 1024,
    "max_position_embeddings": 1024,
    "min_length": 0,
    "model_type": "mbart",
    "no_repeat_ngram_size": 0,
    "normalize_before": true,
    "normalize_embedding": true,
    "num_beam_groups": 1,
    "num_beams": 5,
    "num_hidden_layers": 12,
    "num_return_sequences": 1,
    "output_attentions": false,
    "output_hidden_states": false,
    "output_past": true,
    "output_scores": false,
    "pad_token_id": 1,
    "prefix": null,
    "problem_type": null,
    "pruned_heads": {},
    "remove_invalid_values": false,
    "repetition_penalty": 1.0,
    "return_dict": true,
    "return_dict_in_generate": false,
    "scale_embedding": true,
    "sep_token_id": null,
    "static_position_embeddings": false,
    "task_specific_params": {
      "translation_en_to_ro": {
        "decoder_start_token_id": 250020
      }
    },
    "temperature": 1.0,
    "tie_encoder_decoder": false,
    "tie_word_embeddings": true,
    "tokenizer_class": null,
    "top_k": 50,
    "top_p": 1.0,
    "torch_dtype": null,
    "torchscript": false,
    "transformers_version": "4.10.0",
    "use_bfloat16": false,
    "use_cache": true,
    "vocab_size": 250027
  },
  "index_name": "exact",
  "index_path": null,
  "is_encoder_decoder": true,
  "label_smoothing": 0.0,
  "max_combined_length": 300,
  "model_type": "rag",
  "n_docs": 5,
  "output_retrieved": false,
  "passages_path": null,
  "question_encoder": {
    "_name_or_path": "",
    "add_cross_attention": false,
    "architectures": [
      "DPRQuestionEncoder"
    ],
    "attention_probs_dropout_prob": 0.1,
    "bad_words_ids": null,
    "bos_token_id": null,
    "chunk_size_feed_forward": 0,
    "decoder_start_token_id": null,
    "diversity_penalty": 0.0,
    "do_sample": false,
    "early_stopping": false,
    "encoder_no_repeat_ngram_size": 0,
    "eos_token_id": null,
    "finetuning_task": null,
    "forced_bos_token_id": null,
    "forced_eos_token_id": null,
    "gradient_checkpointing": false,
    "hidden_act": "gelu",
    "hidden_dropout_prob": 0.1,
    "hidden_size": 768,
    "id2label": {
      "0": "LABEL_0",
      "1": "LABEL_1"
    },
    "initializer_range": 0.02,
    "intermediate_size": 3072,
    "is_decoder": false,
    "is_encoder_decoder": false,
    "label2id": {
      "LABEL_0": 0,
      "LABEL_1": 1
    },
    "language": "multilingual",
    "layer_norm_eps": 1e-12,
    "length_penalty": 1.0,
    "max_length": 20,
    "max_position_embeddings": 512,
    "min_length": 0,
    "model_type": "dpr",
    "name": "DPRQuestionEncoder",
    "no_repeat_ngram_size": 0,
    "num_attention_heads": 12,
    "num_beam_groups": 1,
    "num_beams": 1,
    "num_hidden_layers": 12,
    "num_return_sequences": 1,
    "output_attentions": false,
    "output_hidden_states": false,
    "output_scores": false,
    "pad_token_id": 0,
    "position_embedding_type": "absolute",
    "prefix": null,
    "problem_type": null,
    "projection_dim": 0,
    "pruned_heads": {},
    "remove_invalid_values": false,
    "repetition_penalty": 1.0,
    "return_dict": true,
    "return_dict_in_generate": false,
    "revision": null,
    "sep_token_id": null,
    "task_specific_params": null,
    "temperature": 1.0,
    "tie_encoder_decoder": false,
    "tie_word_embeddings": true,
    "tokenizer_class": null,
    "top_k": 50,
    "top_p": 1.0,
    "torch_dtype": null,
    "torchscript": false,
    "transformers_version": "4.10.0",
    "type_vocab_size": 2,
    "use_bfloat16": false,
    "vocab_size": 119547
  },
  "reduce_loss": false,
  "retrieval_batch_size": 8,
  "retrieval_vector_size": 768,
  "title_sep": " / ",
  "torch_dtype": "float32",
  "transformers_version": null,
  "use_cache": true,
  "use_dummy_dataset": false,
  "vocab_size": null
}

Could not locate the tokenizer configuration file, will try to use the model config instead.
Didn't find file /content/checkpoint/question_encoder_tokenizer/added_tokens.json. We won't load it.
loading file /content/checkpoint/question_encoder_tokenizer/vocab.txt
loading file /content/checkpoint/question_encoder_tokenizer/tokenizer.json
loading file None
loading file /content/checkpoint/question_encoder_tokenizer/special_tokens_map.json
loading file /content/checkpoint/question_encoder_tokenizer/tokenizer_config.json
Could not locate the tokenizer configuration file, will try to use the model config instead.
Didn't find file /content/checkpoint/generator_tokenizer/sentencepiece.bpe.model. We won't load it.
Didn't find file /content/checkpoint/generator_tokenizer/added_tokens.json. We won't load it.
loading file None
loading file /content/checkpoint/generator_tokenizer/tokenizer.json
loading file None
loading file /content/checkpoint/generator_tokenizer/special_tokens_map.json
loading file /content/checkpoint/generator_tokenizer/tokenizer_config.json
Assigning ['ar_AR', 'cs_CZ', 'de_DE', 'en_XX', 'es_XX', 'et_EE', 'fi_FI', 'fr_XX', 'gu_IN', 'hi_IN', 'it_IT', 'ja_XX', 'kk_KZ', 'ko_KR', 'lt_LT', 'lv_LV', 'my_MM', 'ne_NP', 'nl_XX', 'ro_RO', 'ru_RU', 'si_LK', 'tr_TR', 'vi_VN', 'zh_CN'] to the additional_special_tokens key of the tokenizer
Traceback (most recent call last):
  File "transformers/examples/research_projects/rag/finetune_rag.py", line 617, in <module>
    main(args)
  File "transformers/examples/research_projects/rag/finetune_rag.py", line 554, in main
    model: GenerativeQAModule = GenerativeQAModule(args)
  File "transformers/examples/research_projects/rag/finetune_rag.py", line 157, in __init__
    save_git_info(self.hparams.output_dir)
  File "/content/transformers/examples/research_projects/rag/utils_rag.py", line 145, in save_git_info
    repo_infos = get_git_info()
  File "/content/transformers/examples/research_projects/rag/utils_rag.py", line 160, in get_git_info
    repo = git.Repo(search_parent_directories=True)
  File "/usr/local/lib/python3.7/dist-packages/git/repo/base.py", line 220, in __init__
    self.working_dir = self._working_tree_dir or self.common_dir  # type: Optional[PathLike]
  File "/usr/local/lib/python3.7/dist-packages/git/repo/base.py", line 303, in common_dir
    raise InvalidGitRepositoryError()
git.exc.InvalidGitRepositoryError
```

## Expected behavior

Not having this error.

A workaround could be creating a git repository and making at at least one commit.<|||||>Hi ! Can you try running the command from inside the `transformers` directory ? This way it will be able to find the git info of the `transformers` repo