Code review comment for ~xavpaice/charm-openstack-service-checks/+git/charm-openstack-service-checks:ssl-nagios-checks

I've addressed the latest round of review comments, and squashed commits to one to keep the history a bit cleaner.

Thanks Joel for the +1 earlier, all I've done here is address the nits and squash commits.

Re logging, that's a great plan for the next commit.