update: skip mds deactivation when no mds in inventory
update: skip mds deactivation when no mds in inventory

Let's skip this part of the code if there's no mds node in the
inventory.

Signed-off-by: Guillaume Abrioux <30a9df5a0293a6108675377fa1673f7aa713f915@redhat.com>

ceph/ceph-ansible,ceph/ceph-ansible