GitLab

The "default=True" makes args.do_lower_case always True.

```python
parser.add_argument("--do_lower_case",
                        default=True,
                        action='store_true')
```

Error occurs when `bert_model` param is path or url. Therefore, if it is path, specify the last path to prevent error.

Division makes args.train_batch_size becoming a float.
cc @thomwolf