Merge remote-tracking branch 'origin/wip-mds-names'

diff --cc src/common/config_opts.h
Simple merge

diff --cc src/mds/MDS.cc
Simple merge

diff --cc src/mds/MDSMap.h
Simple merge

diff --cc src/mon/MDSMonitor.cc
Simple merge

diff --cc src/mon/MDSMonitor.h
Simple merge