res_stasis: trigger cleanup after update

The cleanup code in stasis shuts down applications if they are in a deactivated
state, and no longer have explicit subscriptions. When registering an app the
cleanup code was running before calling 'update'. When it should be executed
after 'update' since a call to register may re-activate the app. We don't want
it to shutdown before the 'update' otherwise the app won't be re-activated,
or registered.

This patch makes it so the cleanup code is executed post 'update'.

ASTERISK-28679 #close

Change-Id: I8f2c0b17e33bb8128441567b97fd4c7bf74a327b
(cherry picked from commit 1051227dd9)

res/res_stasis.c

@@ -1688,12 +1688,11 @@ static int __stasis_app_register(const char *app_name, stasis_app_cb handler, vo
 	if (app) {
 		/*
 		 * We need to unlock the apps_registry before calling app_update to
-		 * prevent the possibility of a deadlock with the session.  We'll still
-		 * run the lazy cleanup first though.
+		 * prevent the possibility of a deadlock with the session.
 		 */
-		cleanup();
 		ao2_unlock(apps_registry);
 		app_update(app, handler, data);
+		cleanup();
 		return 0;
 	}
 
@@ -1718,11 +1717,12 @@ static int __stasis_app_register(const char *app_name, stasis_app_cb handler, vo
 	}
 	ao2_link_flags(apps_registry, app, OBJ_NOLOCK);
 
+	ao2_unlock(apps_registry);
+
 	/* We lazily clean up the apps_registry, because it's good enough to
 	 * prevent memory leaks, and we're lazy.
 	 */
 	cleanup();
-	ao2_unlock(apps_registry);
 	return 0;
 }