If multiple mons are specified in 'ceph-deploy new', but less than
those necessary for quorum are started with 'ceph-deploy mon create',
later steps (like 'ceph-deploy gatherkeys') will fail.
When using ceph-deploy to create a new monitor on a host that is not
in the initial set of hosts defined by the ceph-deploy new command,
a "public network" statement needs to be added to the ceph.conf file.
Fixes#5195.
Signed-off-by: Gary Lowell <gary.lowell@inktank.com>
