Revert "OSD: move waiting_for_pg into Session"

This reverts commit ecda2fef8ce982df3581a3b47ba74ae581d82479.

This leaves Session* refs indefinitely in the map.

This was one source of #7995.

Signed-off-by: Sage Weil <sage@inktank.com>
osd: clear Sessions for loopback Connections on shutdown

Starting with the fast dispatch patches, we are calling the handle_connect
on loopback.  Make sure we zap them on shutdown to break the Session <->
Connection ref cycle.

Signed-off-by: Sage Weil <sage@inktank.com>
osd: fix session leak when waiting on map

We don't want to leak the Session if this Session is already waiting on
a map.

Introduced by eb30f88c942d80cbc951d4d0f375479069d15624.

Signed-off-by: Sage Weil <sage@inktank.com>
osd: clear sessions_waiting_on_map on shutdown

Wake up these ops and drop the Session refs on shutdown.

Signed-off-by: Sage Weil <sage@inktank.com>
Merge pull request #2081 from ceph/wip-osd-leaks

osd: fix several memory leaks from fast dispatch

Reviewed-by: Samuel Just <sam.just@inktank.com>