mgr: play 'enable modules' sequence only on luminous
mgr: play 'enable modules' sequence only on luminous

This feature isn't available before luminous, therefore, we need to play
them only on luminous and after otherwise the playbook will fail.

Signed-off-by: Guillaume Abrioux <30a9df5a0293a6108675377fa1673f7aa713f915@redhat.com>
(cherry picked from commit 3f3d4b9c727d06154c422d445fc2a245aceaed89)

ceph/ceph-ansible,travmi/ceph-ansible,ceph/ceph-ansible,jtaleric/ceph-ansible,font/ceph-ansible,travmi/ceph-ansible,fgal/ceph-ansible,jtaleric/ceph-ansible,font/ceph-ansible,fgal/ceph-ansible