upgrade: block upgrade when rgw multisite is active
upgrade: block upgrade when rgw multisite is active

With this commit, upgrading a cluster from Nautilus to Pacific with
active rgw multisite replication will be blocked.
This is because a lot of bugs are currently present in Pacific regarding
RGW multisite.

Closes: https://bugzilla.redhat.com/show_bug.cgi?id=2063702

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

ceph/ceph-ansible,ceph/ceph-ansible