mgr/rbd_support: refresh schedule queue immediately after delay elapses

mgr/rbd_support: refresh schedule queue immediately after delay elapses

The existing logic often leads to refresh_pools() and refresh_images()
being invoked after a 120 second delay instead of after an intended 60
second delay.

Signed-off-by: Ilya Dryomov <idryomov@gmail.com>
(cherry picked from commit ef3edd399adc99f3ff2acf580727d3dd5439d862)

Conflicts:
	src/pybind/mgr/rbd_support/mirror_snapshot_schedule.py [ commit
	  e4a16e261370 ("mgr/rbd_support: add type annotation") not in
	  pacific ]
	src/pybind/mgr/rbd_support/trash_purge_schedule.py [ ditto ]