Remove "Setting `pad_token_id` to `eos_token_id`:50256 for open-end generation."
When using GPT2 for generation, there is always info:

> Setting `pad_token_id` to `eos_token_id`:50256 for open-end generation

I find this message hides in https://github.com/huggingface/transformers/blob/master/src/transformers/generation_utils.py
It seems redundancy. Can it be removed for simplicity ?

@patrickvonplaten @patil-suraj 
+1, it seems like this method gets triggered on each call to open-ended generation, which pollutes logs quite a bit :/ Is there a way to have it run just once on `pipeline` creation?<|||||>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/master/CONTRIBUTING.md) are likely to be ignored.<|||||>You can manually set the pad_token_id to prevent this error message before running the pipeline, e.g.

```python
gen_pipe = pipeline("text-generation")
gen_pipe.model.config.pad_token_id = gen_pipe.model.config.eos_token_id
```<|||||>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/master/CONTRIBUTING.md) are likely to be ignored.