Merge pull request #6555 from mslovy/wip-reduce-omap-transaction

osd: don't update epoch and rollback_info objects attrs if there is no need

Reviewed-by: Sage Weil <sage@redhat.com>

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

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

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

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

diff --cc src/tools/ceph_objectstore_tool.cc
Simple merge