core: Support decreasing dc compatbility version

Under some scenarios it is possible to decrease a dc compatability version.
This patch adds support for this.

Change-Id: I3bb99e4773ee5592483ad055b277641ebc63cae1
Bug-Url: https://bugzilla.redhat.com/1057029
Signed-off-by: lzelkha@redhat.com <lzelkha@redhat.com>