Merge pull request #16020 from jcsp/wip-20383

mgr: clean up daemon start process

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

diff --cc src/mgr/Mgr.cc
Simple merge

diff --cc src/mgr/Mgr.h
Simple merge

diff --cc src/mgr/MgrStandby.cc
Simple merge

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