Comment 3 for bug 1825466

I have also encountered the same error when I was trying to put a large object with a Chinese object name using S3 Multipart Upload.

After the `obj_name` was decoded with `utf-8`, it seemed to work well.

```
                 if not isinstance(obj_name, six.text_type):
                     obj_name = obj_name.decode('utf-8')
```