notifier: Chain up to parents constructed() before doing anything else

Not strictly needed here, because we don't depend on the parent being
constructed but this is how it should generally be done.

src/calls-notifier.c

@@ -146,6 +146,8 @@ calls_notifier_constructed (GObject *object)
   GList *c;
   CallsNotifier *self = CALLS_NOTIFIER (object);
 
+  G_OBJECT_CLASS (calls_notifier_parent_class)->constructed (object);
+
   g_signal_connect_swapped (calls_manager_get_default (),
                             "ui-call-added",
                             G_CALLBACK (call_added_cb),
@@ -156,8 +158,6 @@ calls_notifier_constructed (GObject *object)
     {
       call_added_cb (self, c->data);
     }
-
-  G_OBJECT_CLASS (calls_notifier_parent_class)->constructed (object);
 }