ceph: --dump-perf-counters[-schema] sockpath
ceph: --dump-perf-counters[-schema] sockpath

Quick and dirty way to dump perfcounters stats.  Not documenting this until
we decide this is where it should live.

Signed-off-by: Sage Weil <6dd34506bbd5e58221bbb3e4732d97c91f02277b@newdream.net>

ajnelson/ceph,ajnelson/ceph,ajnelson/ceph,ajnelson/ceph,ajnelson/ceph,ajnelson/ceph