This reverts commit 3189ba19a7, reversing
changes made to b7620de020.
Despite the change in json format being positive, the unfortunate side-effect
is that it broke upgrade testing (because the QA framework must handle the
transition of mdsmap["info"] to a list from object) and the ceph-mgr.
Fixes: http://tracker.ceph.com/issues/22527
Signed-off-by: Patrick Donnelly <pdonnell@redhat.com>