test: build mimic if more than one release is impacted
test: build mimic if more than one release is impacted

When triggering a build, if more than one distro is impacted by the
change, let's build on the latest release of ceph, currently mimic.

Signed-off-by: Sébastien Han <62d754cc350e84d3b1c32ae79f976f5348e74a40@redhat.com>

ceph/ceph-docker,ceph/ceph-docker