Merge PR #25599 into master

* refs/pull/25599/head:
	mds: do not log internal journal error
	mds: clean up log level 2 messages
	mds: log session open stats

Reviewed-by: Zheng Yan <zyan@redhat.com>

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

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

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

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