Fix __qualname__ assertion on alertmanager

deluge/core/alertmanager.py

@@ -174,7 +174,7 @@ def handle_alerts(self):
                 d = task.deferLater(reactor, 0, handler, alert)
                 on_handler_timeout = partial(
                     self.on_delayed_call_timeout,
-                    handler=handler.__qualname__,
+                    handler=handler.__class__.__qualname__,
                     alert_type=alert_type,
                 )
                 d.addTimeout(