error load bert model ：not found model file
Error content:
OSError: Error no file named ['pytorch_model.bin', 'tf_model.h5', 'model.ckpt.index'] found in directory ./uncased_L-12_H-768_A-12_transformers or `from_tf` set to False
but file exists
![image](https://user-images.githubusercontent.com/11927058/67140873-4d259880-f291-11e9-8e27-25ae7fb661f7.png)

I don't understand when you get this error?<|||||>In order to understand when you've encountered this bug, as suggested by @iedmrc , you've to write down the source code that generates the bug! And please show your environment (Python, Transformers, PyTorch, TensorFlow versions) too! 

> Error content:
> OSError: Error no file named ['pytorch_model.bin', 'tf_model.h5', 'model.ckpt.index'] found in directory ./uncased_L-12_H-768_A-12_transformers or `from_tf` set to False
> but file exists
> ![image](https://user-images.githubusercontent.com/11927058/67140873-4d259880-f291-11e9-8e27-25ae7fb661f7.png)<|||||>This issue has been automatically marked as stale because it has not had recent activity. It will be closed if no further activity occurs. Thank you for your contributions.
<|||||>I got the same error when loading a TF BERT model: 
```
dir = "/Users/danielk/ideaProjects/farsi-language-models/src/models/perbert_L-12_H-768_A-12/"
tokenizer = BertTokenizer.from_pretrained(dir)
config = BertConfig.from_json_file(dir + '/bert_config.json')
model = TFBertForMaskedLM.from_pretrained(dir, config=config)
```
The error happens in the last line. 
```
Traceback (most recent call last):
  File "6.2.try_tf_bert_transformers.py", line 8, in <module>
    model = TFBertForMaskedLM.from_pretrained(dir, config=config)
  File "/Users/danielk/opt/anaconda3/lib/python3.7/site-packages/transformers/modeling_tf_utils.py", line 353, in from_pretrained
    [WEIGHTS_NAME, TF2_WEIGHTS_NAME], pretrained_model_name_or_path
OSError: Error no file named ['pytorch_model.bin', 'tf_model.h5'] found in directory /Users/danielk/ideaProjects/farsi-language-models/src/models/perbert_L-12_H-768_A-12/ or `from_pt` set to False
```