Fixed wrong help message shown on '--help'
Summary:
Correct help message was obfuscated by the transient `ArgumentParser` used only for eagerly read `--user-dir` flag.
To reproduce just try:
```bash
python3 train.py --help
```
Pull Request resolved:
@@ -124,7 +124,7 @@ def parse_args_and_arch(parser, input_args=None, parse_known=False):
def get_parser(desc, default_task='translation'):
# Before creating the true parser, we need to import optional user module
# in order to eagerly import custom tasks, optimizers, architectures, etc.
- usr_parser = argparse.ArgumentParser()
+ usr_parser = argparse.ArgumentParser(add_help=False)
usr_parser.add_argument('--user-dir', default=None)
usr_args, _ = usr_parser.parse_known_args()
