Dumpling osd pgstatsack

This is a Dumpling backport (fairly trivial) of a branch that cleans up how the OSD handles timing out a monitor connection. With these changes, it will not connect to a monitor and then disconnect partway through the work that the monitor does on behalf of the OSD as part of the connection handshakes.
(This behavior was part of a cascade event we saw on a large production cluster; it eventually cleaned itself up but these changes would have made the cleanup much faster.)