ResourceNotFoundException for seemingly every get call?

`awslogs get --region us-east-1 /aws/lambda/us-east-1.nameofmyfunction`

```
Traceback (most recent call last):
File "/usr/local/bin/awslogs", line 11, in
sys.exit(main())
File "/usr/local/lib/python2.7/site-packages/awslogs/bin.py", line 172, in main
getattr(logs, options.func)()
File "/usr/local/lib/python2.7/site-packages/awslogs/core.py", line 76, in list_logs
streams = list(self._get_streams_from_pattern(self.log_group_name, self.log_stream_name))
File "/usr/local/lib/python2.7/site-packages/awslogs/core.py", line 69, in _get_streams_from_pattern
for stream in self.get_streams(group):
File "/usr/local/lib/python2.7/site-packages/awslogs/core.py", line 228, in get_streams
for page in paginator.paginate(**kwargs):
File "/usr/local/lib/python2.7/site-packages/botocore/paginate.py", line 255, in __iter__
response = self._make_request(current_kwargs)
File "/usr/local/lib/python2.7/site-packages/botocore/paginate.py", line 332, in _make_request
return self._method(**current_kwargs)
File "/usr/local/lib/python2.7/site-packages/botocore/client.py", line 314, in _api_call
return self._make_api_call(operation_name, kwargs)
File "/usr/local/lib/python2.7/site-packages/botocore/client.py", line 612, in _make_api_call
raise error_class(parsed_response, operation_name)
botocore.errorfactory.ResourceNotFoundException: An error occurred (ResourceNotFoundException) when calling the DescribeLogStreams operation: The specified log group does not exist.
```

I get this same error no matter what logs I seem to call.

On:
macOS 10.13.6
pip 10.0.1
Python 2.7.15

Reproduce the reported awslogs command and follow the traceback through awslogs/core.py, especially list_logs, _get_streams_from_pattern, and get_streams. Check how the log group name is passed to DescribeLogStreams and compare the observed behavior with the reported ResourceNotFoundException; done means the command handles or explains this case correctly.

Written by the indexing model from the issue text.