Specifying asterisk as query causes error

I ran `awslogs get MY_STREAM_NAME '*'` and error as below:
```
Version: 0.10.0
Python: 3.7.0 (default, Jul 15 2018, 10:44:58)
[GCC 8.1.1 20180531]
boto3 version: 1.9.10
Platform: Linux-4.14.70-1-MANJARO-x86_64-with-arch-Manjaro-Linux
Config: {'aws_access_key_id': 'SENSITIVE', 'aws_secret_access_key': 'SENSITIVE', 'aws_session_token': 'SENSITIVE', 'aws_profile': 'SENSITIVE', 'aws_region': None, 'log_group_name': 'MY_STREAM_NAME', 'log_stream_name': '*', 'filter_pattern': None, 'watch': False, 'output_group_enabled': True, 'output_stream_enabled': True, 'output_timestamp_enabled': False, 'output_ingestion_time_enabled': False, 'start': '5m', 'end': None, 'color_enabled': True, 'query': None, 'func': 'list_logs'}
Args: ['/home/picosushi/.local/bin/awslogs', 'get', 'MY_STREAM_NAME', '*']

Traceback (most recent call last):
File "/home/picosushi/.local/lib/python3.7/site-packages/awslogs/bin.py", line 172, in main
getattr(logs, options.func)()
File "/home/picosushi/.local/lib/python3.7/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 "/home/picosushi/.local/lib/python3.7/site-packages/awslogs/core.py", line 68, in _get_streams_from_pattern
reg = re.compile('^{0}'.format(pattern))
File "/usr/lib/python3.7/re.py", line 234, in compile
return _compile(pattern, flags)
File "/usr/lib/python3.7/re.py", line 286, in _compile
p = sre_compile.compile(pattern, flags)
File "/usr/lib/python3.7/sre_compile.py", line 764, in compile
p = sre_parse.parse(p, flags)
File "/usr/lib/python3.7/sre_parse.py", line 930, in parse
p = _parse_sub(source, pattern, flags & SRE_FLAG_VERBOSE, 0)
File "/usr/lib/python3.7/sre_parse.py", line 426, in _parse_sub
not nested and not items))
File "/usr/lib/python3.7/sre_parse.py", line 651, in _parse
source.tell() - here + len(this))
re.error: nothing to repeat at position 1
```

Start with awslogs/core.py at _get_streams_from_pattern and list_logs, then reproduce `awslogs get MY_STREAM_NAME '*'` to inspect the reported regular-expression failure. Done means the command no longer errors when `*` is supplied as the stream pattern and the expected logs can be listed.

Written by the indexing model from the issue text.