Fix import error of tf 2.4.1 on TPU.
Author: innat
Pull request: yes

# What does this PR do?

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The import of https://github.com/huggingface/transformers/blob/06a6a4bd516f7d0ba7c4966a2d3d9c0bf07797ae/src/transformers/modeling_tf_utils.py#L39

should be 

```python
from tensorflow.python.keras.saving.hdf5_format import save_attributes_to_hdf5_group
```

Otherwise, model like CLIP-TensorFlow can't import in TF 2.4.1 on TPU (kaggle env).

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Comments:
_The documentation is not available anymore as the PR was closed or merged._

@sgugger 
Could you please take a look into this? It's a very short fix.

@gante, could you take a look at this?

It seems there is an issue with your CircleCI permissions, the tests won't run.
Could you try refreshing your permissions as shown [here](https://support.circleci.com/hc/en-us/articles/360048210711-How-to-Refresh-User-Permissions-)?

Hey @innat -- the change looks good, but we still want to default to the public namespace.

Can you wrap the import in a try/except block? (try importing the original, and import the line you added if it fails)

@gante I think it's done. Please check.

This issue has been automatically marked as stale because it has not had recent activity. If you think this still needs to be addressed please comment on this thread.

Please note that issues that do not follow the [contributing guidelines](https://github.com/huggingface/transformers/blob/main/CONTRIBUTING.md) are likely to be ignored.

Hi @innat -- can you have a look at Lysandre's comment, to allow CI to run?

Alternatively, you can follow [this guide](https://docs.github.com/en/pull-requests/collaborating-with-pull-requests/working-with-forks/allowing-changes-to-a-pull-request-branch-created-from-a-fork) to give me write access over this PR, and I'll take care of the rest :)