ceph-defaults: fix handlers for mds and rgw

ceph-defaults: fix handlers for mds and rgw

The way we handle the restart for both mds and rgw is not ideal, it will
try to restart the daemon on the host that don't run the daemon,
resulting in a service file being created (see bug description).

Now we restart each daemon precisely and in a serialized fashion.

Note: the current implementation does NOT support multiple mds or rgw on
the same node.

Closes: https://bugzilla.redhat.com/show_bug.cgi?id=1469781
Signed-off-by: Sébastien Han <seb@redhat.com>