Missing xlm-mlm-100-1280
## 🐛 Bug

For some reason I can't download the xlm-mlm-100-1280 model for tensorflow 2.0

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

Language I am using the model on (English, Chinese....): 100 languages

The problem arise when using:
```TFXLMForSequenceClassification.from_pretrained("xlm-mlm-100-1280")```

## Expected behavior

Being able to download the model as for the other configuration

## Environment

* OS: Ubuntu 16.04
* Python version: 3.7.5
* Using GPU : yes
* Distributed of parallel setup : distributed
* Tensorflow 2.0
* transformers version 2.1.1

It works with **PyTorch**, but not with **TensorFlow**. I'm using Python 3.6.9, Transformers 2.2.1 (installed with `pip install transformers`), PyTorch 1.3.1 and TensorFlow 2.0.0.
With TensorFlow, the stack trace is the following:
```
> from transformers import TFXLMForSequenceClassification
> model = TFXLMForSequenceClassification.from_pretrained("xlm-mlm-100-1280")
100%|████████████████████████████████████████████████████████████████████████████████████████████████████████████████████████████████████████████████████████████████████████████████████████████████████████████████████████| 41478/41478 [00:00<00:00, 365198.30B/s]
304B [00:00, 133069.13B/s]
2019-12-04 10:44:05.684050: W tensorflow/python/util/util.cc:299] Sets are not currently considered sequences, but this may change in the future, so consider avoiding using them.
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File "/home/<user>/anaconda3/envs/huggingface/lib/python3.6/site-packages/transformers/modeling_tf_utils.py", line 289, in from_pretrained
    model.load_weights(resolved_archive_file, by_name=True)
  File "/home/<user>/anaconda3/envs/huggingface/lib/python3.6/site-packages/tensorflow_core/python/keras/engine/training.py", line 181, in load_weights
    return super(Model, self).load_weights(filepath, by_name)
  File "/home/<user>/anaconda3/envs/huggingface/lib/python3.6/site-packages/tensorflow_core/python/keras/engine/network.py", line 1171, in load_weights
    with h5py.File(filepath, 'r') as f:
  File "/home/<user>/anaconda3/envs/huggingface/lib/python3.6/site-packages/h5py/_hl/files.py", line 408, in __init__
    swmr=swmr)
  File "/home/<user>/anaconda3/envs/huggingface/lib/python3.6/site-packages/h5py/_hl/files.py", line 173, in make_fid
    fid = h5f.open(name, flags, fapl=fapl)
  File "h5py/_objects.pyx", line 54, in h5py._objects.with_phil.wrapper
  File "h5py/_objects.pyx", line 55, in h5py._objects.with_phil.wrapper
  File "h5py/h5f.pyx", line 88, in h5py.h5f.open
OSError: Unable to open file (file signature not found)
```

If you want, with TensorFlow, it works the XLM model with config **xlm-mlm-17-1280**, which is a Masked Language Modeling with 17 languages.
```
> from transformers import TFXLMForSequenceClassification
> model = TFXLMForSequenceClassification.from_pretrained("xlm-mlm-17-1280")
100%|█████████████████████████████████████████████████████████████████████████████████████████████████████████████████████████████████████████████████████████████████████████████████████████████████████████████| 3311066864/3311066864 [05:40<00:00, 9737775.86B/s]
```

> ##  Bug
> For some reason I can't download the xlm-mlm-100-1280 model for tensorflow 2.0
> 
> Model I am using (Bert, XLNet....): XLM
> 
> Language I am using the model on (English, Chinese....): 100 languages
> 
> The problem arise when using:
> `TFXLMForSequenceClassification.from_pretrained("xlm-mlm-100-1280")`
> 
> ## Expected behavior
> Being able to download the model as for the other configuration
> 
> ## Environment
> * OS: Ubuntu 16.04
> * Python version: 3.7.5
> * Using GPU : yes
> * Distributed of parallel setup : distributed
> * Tensorflow 2.0
> * transformers version 2.1.1<|||||>Yes I'm refearing to TF2 and I'm currently using ``xlm-mlm-17-1280``, but I wanted to use the bigger model to see if I was able to achieve better performances.

At the moment I'm quite disappointed with xlm-mlm-17-1280, but it might be my fault.<|||||>If you suspect that you're in trouble, please copy and paste your code here and discuss together

> Yes I'm refearing to TF2 and I'm currently using `xlm-mlm-17-1280`, but I wanted to use the bigger model to see if I was able to achieve better performances.
> 
> At the moment I'm quite disappointed with xlm-mlm-17-1280, but it might be my fault.

<|||||>Indeed, this one is missing from the S3. Adding it now!<|||||>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.
