Fix some pep8
Remove check_dns arg from minion_config, Fixes #4811

All use of the check_dns arg was removed in
598d715d28b15202cdba87b6882ef96c90d4f075.  No longer needed.

Arg was removed from both apply_minion_config and minion_config in
config.py, as well as all their call points.
Add **kwargs so we don't break API calls
Merge pull request #4950 from basepi/check_dns

Remove check_dns arg from minion_config, Fixes #4811