HA support for radosgw

Depends on https://github.com/crowbar/barclamp-pacemaker/pull/129
Oops: when HA is being used, we should not listen on `node['ceph']['radosgw']['rgw_addr']` but on the admin IP address of the node. This is critical when the address is not `*` (otherwise, haproxy will not be able to reach radosgw), but important even in that `*` case as we don't want people to be able to reach directly servers -- we want them to go to haproxy.