OSD::session_notify_pg_create: requeue at the start of the queue

Introduced: 2120f4bb6c5ba0f066d4541a51ce1d43c8ab6881
Fixes: #9205
Signed-off-by: Samuel Just <sam.just@inktank.com>
Merge pull request #2347 from athanatos/wip-9205

OSD::session_notify_pg_create: requeue at the start of the queue

Reviewed-by: Sage Weil <sage@redhat.com>