Ceph

Make it so that forming an initial quorum is only possible if the
majority of members from a "initial members" are participating in the
quorum. Take this list of initial members from (in this order, stop at
first variable that is set):
1. mon initial members = id1, id2, id3, ...
2. mon initial hosts = host_or_ip[:port], host_or_ip[:port], ...
3. mon hosts = host_or_ip[:port], host_or_ip[:port], ...