don't complain about missing W&B when WANDB_DISABLED=true
Author: stas00
Pull request: yes

I get a lot of crashes with W&B in transformers examples: https://github.com/huggingface/transformers/pull/5835 so I have to use `WANDB_DISABLED=true` - this PR removes a complaint that shouldn't be there when this env var is used.

Comments:
# [Codecov](https://codecov.io/gh/huggingface/transformers/pull/6036?src=pr&el=h1) Report
> Merging [#6036](https://codecov.io/gh/huggingface/transformers/pull/6036?src=pr&el=desc) into [master](https://codecov.io/gh/huggingface/transformers/commit/c69ea5efc4eac65b183e8d07b1bf91d20bbe0c8c&el=desc) will **decrease** coverage by `1.18%`.
> The diff coverage is `50.00%`.

[![Impacted file tree graph](https://codecov.io/gh/huggingface/transformers/pull/6036/graphs/tree.svg?width=650&height=150&src=pr&token=9qOlN6Hb1c)](https://codecov.io/gh/huggingface/transformers/pull/6036?src=pr&el=tree)

```diff
@@            Coverage Diff             @@
##           master    #6036      +/-   ##
==========================================
- Coverage   78.50%   77.31%   -1.19%     
==========================================
  Files         146      146              
  Lines       26249    26251       +2     
==========================================
- Hits        20606    20297     -309     
- Misses       5643     5954     +311     
```


| [Impacted Files](https://codecov.io/gh/huggingface/transformers/pull/6036?src=pr&el=tree) | Coverage Δ | |
|---|---|---|
| [src/transformers/trainer\_tf.py](https://codecov.io/gh/huggingface/transformers/pull/6036/diff?src=pr&el=tree#diff-c3JjL3RyYW5zZm9ybWVycy90cmFpbmVyX3RmLnB5) | `16.47% <0.00%> (-0.07%)` | :arrow_down: |
| [src/transformers/trainer.py](https://codecov.io/gh/huggingface/transformers/pull/6036/diff?src=pr&el=tree#diff-c3JjL3RyYW5zZm9ybWVycy90cmFpbmVyLnB5) | `41.00% <100.00%> (+0.12%)` | :arrow_up: |
| [src/transformers/modeling\_tf\_mobilebert.py](https://codecov.io/gh/huggingface/transformers/pull/6036/diff?src=pr&el=tree#diff-c3JjL3RyYW5zZm9ybWVycy9tb2RlbGluZ190Zl9tb2JpbGViZXJ0LnB5) | `23.38% <0.00%> (-73.39%)` | :arrow_down: |
| [src/transformers/file\_utils.py](https://codecov.io/gh/huggingface/transformers/pull/6036/diff?src=pr&el=tree#diff-c3JjL3RyYW5zZm9ybWVycy9maWxlX3V0aWxzLnB5) | `81.49% <0.00%> (+0.29%)` | :arrow_up: |
| [src/transformers/generation\_tf\_utils.py](https://codecov.io/gh/huggingface/transformers/pull/6036/diff?src=pr&el=tree#diff-c3JjL3RyYW5zZm9ybWVycy9nZW5lcmF0aW9uX3RmX3V0aWxzLnB5) | `86.21% <0.00%> (+0.75%)` | :arrow_up: |
| [src/transformers/modeling\_tf\_roberta.py](https://codecov.io/gh/huggingface/transformers/pull/6036/diff?src=pr&el=tree#diff-c3JjL3RyYW5zZm9ybWVycy9tb2RlbGluZ190Zl9yb2JlcnRhLnB5) | `93.36% <0.00%> (+49.37%)` | :arrow_up: |

------

[Continue to review full report at Codecov](https://codecov.io/gh/huggingface/transformers/pull/6036?src=pr&el=continue).
> **Legend** - [Click here to learn more](https://docs.codecov.io/docs/codecov-delta)
> `Δ = absolute <relative> (impact)`, `ø = not affected`, `? = missing data`
> Powered by [Codecov](https://codecov.io/gh/huggingface/transformers/pull/6036?src=pr&el=footer). Last update [c69ea5e...f1463a0](https://codecov.io/gh/huggingface/transformers/pull/6036?src=pr&el=lastupdated). Read the [comment docs](https://docs.codecov.io/docs/pull-request-comments).


LGTM

Note, the project has a failing test - I did 2 PRs updates yesterday and today - both unrelated to my work
https://app.circleci.com/pipelines/github/huggingface/transformers/9539/workflows/15fcbc84-9cfe-4970-943f-935bce800c98/jobs/64765

another one from last night:
https://app.circleci.com/pipelines/github/huggingface/transformers/9527/workflows/73306d70-4190-48cd-b24a-b73619cd2002/jobs/64665/steps

Please kindly trigger a re-run of CI for this PR. Thank you.


Yeah, the CI is flaky sometimes. Re-triggered the failing test.

> Yeah, the CI is flaky sometimes. 

When it happens it's the same test that fails - perhaps it could be fixed?

> Re-triggered the failing test.

Thank you, @sgugger 


Yeah we try to fix those flaky tests as we catch them. Don't hesitate to report the name and logs on your own too.