Exclude /etc/hostname
Exclude /etc/hostname

Similar to the previous patch where we excluded /etc/hosts, it turns out
that /etc/hostname is also a special file that cannot be synced in via
kolla because they are bindmounted internally.

https://github.com/containers/libpod/blob/6ac009d5304127f6758be157c7302646e5a481e5/libpod/container_internal_linux.go#L1236

Additionally this change includes cleanup for end users who may have hit
LP#1860607 and allows folks who have hit this to just simply rerun the
deployment and not have to manually cleanup the synced files.

Change-Id: I84287d9c1ef110511c66743f9a3a22709077b0cb
Closes-Bug: #1885619

openstack/tripleo-heat-templates,openstack/tripleo-heat-templates