mds: fix mds standby map handling
mds: fix mds standby map handling

Borken by c6ddbdb4671b3594f9b4d5f54b65f8525935758b

ajnelson/ceph,ajnelson/ceph,ajnelson/ceph,ajnelson/ceph,ajnelson/ceph,ajnelson/ceph