Merge pull request #4227 from tchaikov/node-ls

mon,osd,mds: add "{mon,mds} metadata" and "node ls" commands

Reviewed-by: Joao Eduardo Luis <joao@suse.de>

diff --cc qa/workunits/cephtool/test.sh
Simple merge

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

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