Merge pull request #610 from ceph/wip-optracker

Reviewed-by: Samuel Just <sam.just@inktank.com>

diff --cc src/osd/PG.cc
Simple merge

diff --cc src/osd/ReplicatedBackend.cc
Simple merge

diff --cc src/osd/ReplicatedPG.cc
Simple merge

diff --cc src/osd/ReplicatedPG.h
Simple merge

diff --cc src/test/encoding/types.h
Simple merge