Remove old non-gz files in log archive maintenance

* modules/openstack_project/files/log_archive_maintenance.sh: Start
matching for removal on any files in the logs tree besides those we
explicitly don't compress. Also do it via a refactor to allow for
improved optimization and avoid unnecessary redundancy.

Change-Id: I5ff6defb4d403f3017ab098c2ac1df3777662933
Merge "Remove old non-gz files in log archive maintenance"