Fix support for --env-file in bash completion

The `--env-file` option of `docker run` and `docker create` in bash completion is not implemented properly.

To reproduce:
* In bash, type `docker run --en` and tab twice. The available completions will be: `--entrypoint  --env`
* In bash, type `docker create --en` and tab twice. The available completions will be: `--entrypoint  --env`

This PR adds the missing option.