Update provider.py

```
  File "/usr/local/lib/python2.7/dist-packages/boto/gs/connection.py", line 47, in __init__
    suppress_consec_slashes=suppress_consec_slashes)
  File "/usr/local/lib/python2.7/dist-packages/boto/s3/connection.py", line 190, in __init__
    validate_certs=validate_certs, profile_name=profile_name)
  File "/usr/local/lib/python2.7/dist-packages/boto/connection.py", line 558, in __init__
    profile_name)
  File "/usr/local/lib/python2.7/dist-packages/boto/provider.py", line 197, in __init__
    self.get_credentials(access_key, secret_key, security_token, profile_name)
  File "/usr/local/lib/python2.7/dist-packages/boto/provider.py", line 268, in get_credentials
    if profile_name is None and profile_name_name.upper() in os.environ:
AttributeError: 'NoneType' object has no attribute 'upper'
```