CI: Add https match for mirror.centos.org to template-overrides
CI: Add https match for mirror.centos.org to template-overrides

Some CentOS repos (currently one - Ceph NFS Ganesha) use
https://mirror.centos.org instead of http:// and we break
their definition by removing mirrorlist= entry and not inserting baseurl
entry due to a missing match.

Change-Id: I7b29f8c6be80820042023d2b85162d5cc9a65f08

openstack/kolla,stackforge/kolla,stackforge/kolla,stackforge/kolla,openstack/kolla