Fix some looping_call calls which were broken in #3604

It turns out that looping_call does check the deferred returned by its
callback, and (at least in the case of client_ips), we were relying on this,
and I broke it in #3604.

Update run_as_background_process to return the deferred, and make sure we
return it to clock.looping_call.

1 files changed, 2 insertions, 2 deletions

diff --git a/synapse/storage/event_push_actions.py b/synapse/storage/event_push_actions.py

index 4f44b0ad47..6840320641 100644
--- a/synapse/storage/event_push_actions.py
+++ b/synapse/storage/event_push_actions.py
@@ -460,7 +460,7 @@ class EventPushActionsWorkerStore(SQLBaseStore):
             )
 
     def _find_stream_orderings_for_times(self):
-        run_as_background_process(
+        return run_as_background_process(
             "event_push_action_stream_orderings",
             self.runInteraction,
             "_find_stream_orderings_for_times",
@@ -790,7 +790,7 @@ class EventPushActionsStore(EventPushActionsWorkerStore):
         """, (room_id, user_id, stream_ordering))
 
     def _start_rotate_notifs(self):
-        run_as_background_process("rotate_notifs", self._rotate_notifs)
+        return run_as_background_process("rotate_notifs", self._rotate_notifs)
 
     @defer.inlineCallbacks
     def _rotate_notifs(self):