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, 1 insertions, 1 deletions

diff --git a/synapse/handlers/profile.py b/synapse/handlers/profile.py

index 43692b83a8..cb5c6d587e 100644
--- a/synapse/handlers/profile.py
+++ b/synapse/handlers/profile.py
@@ -256,7 +256,7 @@ class ProfileHandler(BaseHandler):
                 )
 
     def _start_update_remote_profile_cache(self):
-        run_as_background_process(
+        return run_as_background_process(
             "Update remote profile", self._update_remote_profile_cache,
         )