Fix local file rename rollback

# Drive 4.2.0
AttributeError: 'NoneType' object has no attribute 'rstrip'
  File "nxdrive\engine\processor.py", line 1383, in _handle_failed_remote_rename
  File "nxdrive\client\local_client.py", line 629, in rename
  File "nxdrive\utils.py", line 569, in safe_os_filename
  File "nxdrive\utils.py", line 555, in safe_filename

TypeError: expected string or bytes-like object
File "engine/processor.py", line 1462, in _handle_failed_remote_rename
File "client/local/base.py", line 458, in rename
File "utils.py", line 622, in safe_os_filename
File "utils.py", line 607, in safe_filename
File ".../re.py", line 192, in sub