When private/public network have been defined in the Ceph rook cluster it is not
possible to configure properly the ip address of the liveness probe
for the manager.
Changes in the manager in Pacific introduced this regression.
This change replaces the http probe by a command probe, avoiding thus to
determine what is going to be the ip address of the manager before launching
the pod.
fixes: https://github.com/rook/rook/issues/8510
Signed-off-by: Juan Miguel Olmo Martínez <jolmomar@redhat.com>