Model name 'facebook/rag-sequence-base/*' not found when running examples/rag/finetune.sh
## Environment info
     
- `transformers` version: 3.3.1
- Platform: Linux-4.15.0-38-generic-x86_64-with-Ubuntu-18.04-bionic
- Python version: 3.6.9
- PyTorch version (GPU?): 1.6.0 (True)
- Tensorflow version (GPU?): not installed (NA)
- Using GPU in script?: True
- Using distributed or parallel set-up in script?: True (Retriever is distributed)


### Who can help
@patrickvonplaten, @lhoestq 

## Information

Model I am using (Bert, XLNet ...):

**facebook/rag-sequence-base**

The problem arises when using:
* [x ] the official example scripts: (give details below)
examples/rag/finetune.sh

The tasks I am working on is:
* [x ] my own task or dataset: (give details below)

## To reproduce

Steps to reproduce the behavior:

run `sh finetune.sh`
with 
```
DATA_DIR=data_dir
OUTPUT_DIR=output_dir
MODEL_NAME_OR_PATH="facebook/rag-sequence-base"
```

gives:

**Model name 'facebook/rag-sequence-base/question_encoder_tokenizer' not found in model shortcut name list (facebook/dpr-question_encoder-single-nq-base). Assuming 'facebook/rag-sequence-base/question_encoder_tokenizer' is a path, a model identifier, or url to a directory containing tokenizer files**.
loading file https://s3.amazonaws.com/models.huggingface.co/bert/facebook/rag-sequence-base/question_encoder_tokenizer/vocab.txt from cache at /h/asabet/.cache/torch/transformers/14d599f015518cd5b95b5d567b8c06b265dbbf04047e44b3654efd7cbbacb697.542ce4285a40d23a559526243235df47c5f75c197f04f37d1a0c124c32c9a084
loading file https://s3.amazonaws.com/models.huggingface.co/bert/facebook/rag-sequence-base/question_encoder_tokenizer/added_tokens.json from cache at None
loading file https://s3.amazonaws.com/models.huggingface.co/bert/facebook/rag-sequence-base/question_encoder_tokenizer/special_tokens_map.json from cache at /h/asabet/.cache/torch/transformers/70614c7a84151409876eaaaecb3b5185213aa5c560926855e35753b9909f1116.275045728fbf41c11d3dae08b8742c054377e18d92cc7b72b6351152a99b64e4
loading file https://s3.amazonaws.com/models.huggingface.co/bert/facebook/rag-sequence-base/question_encoder_tokenizer/tokenizer_config.json from cache at /h/asabet/.cache/torch/transformers/8ade9cf561f8c0a47d1c3785e850c57414d776b3795e21bd01e58483399d2de4.11f57497ee659e26f830788489816dbcb678d91ae48c06c50c9dc0e4438ec05b
loading file https://s3.amazonaws.com/models.huggingface.co/bert/facebook/rag-sequence-base/question_encoder_tokenizer/tokenizer.json from cache at None
**Model name 'facebook/rag-sequence-base/generator_tokenizer' not found in model shortcut name list (facebook/bart-base, facebook/bart-large, facebook/bart-large-mnli, facebook/bart-large-cnn, facebook/bart-large-xsum, yjernite/bart_eli5). Assuming 'facebook/rag-sequence-base/generator_tokenizer' is a path, a model identifier, or url to a directory containing tokenizer files.**
loading file https://s3.amazonaws.com/models.huggingface.co/bert/facebook/rag-sequence-base/generator_tokenizer/vocab.json from cache at /h/asabet/.cache/torch/transformers/3b9637b6eab4a48cf2bc596e5992aebb74de6e32c9ee660a27366a63a8020557.6a4061e8fc00057d21d80413635a86fdcf55b6e7594ad9e25257d2f99a02f4be
loading file https://s3.amazonaws.com/models.huggingface.co/bert/facebook/rag-sequence-base/generator_tokenizer/merges.txt from cache at /h/asabet/.cache/torch/transformers/b2a6adcb3b8a4c39e056d80a133951b99a56010158602cf85dee775936690c6a.70bec105b4158ed9a1747fea67a43f5dee97855c64d62b6ec3742f4cfdb5feda
loading file https://s3.amazonaws.com/models.huggingface.co/bert/facebook/rag-sequence-base/generator_tokenizer/added_tokens.json from cache at None
loading file https://s3.amazonaws.com/models.huggingface.co/bert/facebook/rag-sequence-base/generator_tokenizer/special_tokens_map.json from cache at /h/asabet/.cache/torch/transformers/342599872fb2f45f954699d3c67790c33b574cc552a4b433fedddc97e6a3c58e.6e217123a3ada61145de1f20b1443a1ec9aac93492a4bd1ce6a695935f0fd97a
loading file https://s3.amazonaws.com/models.huggingface.co/bert/facebook/rag-sequence-base/generator_tokenizer/tokenizer_config.json from cache at /h/asabet/.cache/torch/transformers/e5f72dc4c0b1ba585d7afb7fa5e3e52ff0e1f101e49572e2caaf38fab070d4d6.d596a549211eb890d3bb341f3a03307b199bc2d5ed81b3451618cbcb04d1f1bc
loading file https://s3.amazonaws.com/models.huggingface.co/bert/facebook/rag-sequence-base/generator_tokenizer/tokenizer.json from cache at None
Traceback (most recent call last):
  File "finetune.py", line 499, in <module>
    main(args)
  File "finetune.py", line 439, in main
    model: GenerativeQAModule = GenerativeQAModule(args)
  File "finetune.py", line 105, in __init__
    retriever = RagPyTorchDistributedRetriever.from_pretrained(hparams.model_name_or_path, config=config)
  File "/h/asabet/.local/lib/python3.6/site-packages/transformers/retrieval_rag.py", line 308, in from_pretrained
    config, question_encoder_tokenizer=question_encoder_tokenizer, generator_tokenizer=generator_tokenizer
  File "/scratch/ssd001/home/asabet/transformers/examples/rag/distributed_retriever.py", line 41, in __init__
    index=index,
**TypeError: __init__() got an unexpected keyword argument 'index'**


## Expected behavior
finetune.sh should launch and run 


Hi, I have a related issue. This happen to `"facebook/rag-token-base"` and `"facebook/rag-token-nq"` and `"facebook/rag-sequence-nq"` as well.

Basic loading failed (was able to do it until  around 2 days ago -- I use version 3.5.0)
Both

`tokenizer = RagTokenizer.from_pretrained("facebook/rag-sequence-nq")`
and
`retriever = RagRetriever.from_pretrained("facebook/rag-token-nq", index_name="exact", use_dummy_dataset=True)`

result in the same error message: 

`OSError: Can't load tokenizer for 'facebook/rag-sequence-nq/question_encoder_tokenizer'.`

<<< Seem like it add the wrong path `question_encoder_tokenizer` at the end.
<|||||>to add to @ratthachat's comment: I observe the same problem when loading the model with:

`model = RagTokenForGeneration.from_pretrained("facebook/rag-token-nq") `
<|||||>Tagging @julien-c @Pierrci here. Maybe an issue related to the migration to git/git-lfs<|||||>Initial poster seems to be running `transformers version: 3.3.1` which makes me suspect it might not be related to the git/git-lfs migration

Update: @lhoestq is looking into it<|||||>@lhoestq @julien-c @thomwolf 
Sorry to ask, but I am translating TFRag and would really love to continue before long hollidays.
Could it be possible to fix only the wrong file path (the last `question_encoder_tokenizer`) in 

`OSError: Can't load tokenizer for 'facebook/rag-sequence-nq/question_encoder_tokenizer'.`

to fix error of basic loading 

```
tokenizer = RagTokenizer.from_pretrained("facebook/rag-sequence-nq")

or

retriever = RagRetriever.from_pretrained("facebook/rag-token-nq", index_name="exact", use_dummy_dataset=True)

or

model = RagTokenForGeneration.from_pretrained("facebook/rag-token-nq")
```<|||||>Apologies for any duplicate comments, but experiencing the same issue as @ratthachat.
Any updates or fixes on this? Currently running transformers-3.5.1<|||||>Hello, feel free to open a PR with your proposed fix and we'll take a look. Thanks!<|||||>Can confirm that this error is eliminated when downgrading to:
```
transformers==3.3.1
tokenizers==0.9.2
datasets==1.1.2
```

Looks very likely that something went wrong in the transition to git-lfs for this use case.

@thomwolf @julien-c <|||||>Thanks for the detailed reports everyone, this should now be fixed on `master`.<|||||>@julien-c 

Hi I am trying to run [use_own_knowledge_dataset.py](https://github.com/huggingface/transformers/blob/master/examples/rag/use_own_knowledge_dataset.py) with **Transformers  Version: 3.5.1**. But it gives the following error.

```

OSError: Can't load tokenizer for 'facebook/rag-sequence-nq/question_encoder_tokenizer'. Make sure that:

- 'facebook/rag-sequence-nq/question_encoder_tokenizer' is a correct model identifier listed on 'https://huggingface.co/models'

- or 'facebook/rag-seq
```uence-nq/question_encoder_tokenizer' is the correct path to a directory containing relevant tokenizer files
<|||||>> @julien-c
> 
> Hi I am trying to run [use_own_knowledge_dataset.py](https://github.com/huggingface/transformers/blob/master/examples/rag/use_own_knowledge_dataset.py) with **Transformers Version: 3.5.1**. But it gives the following error.
> 
> ```
> 
> OSError: Can't load tokenizer for 'facebook/rag-sequence-nq/question_encoder_tokenizer'. Make sure that:
> 
> - 'facebook/rag-sequence-nq/question_encoder_tokenizer' is a correct model identifier listed on 'https://huggingface.co/models'
> 
> - or 'facebook/rag-seq
> ```uence-nq/question_encoder_tokenizer' is the correct path to a directory containing relevant tokenizer files
> ```

Hey @shamanez - could you open a separate issue for this and tag @lhoestq ? :-) <|||||>Sure :) <|||||>The fix is not yet in a released version only on `master`, so you need to install from master for now.<|||||>so shall I install from sources?<|||||>Thank you! When will the fixed version be released?