main.c: return transition error only once

When a plugin activation fails, it is supposed to fail the wireplumber init. To be precise it fails the wp init transition and the init transition objected is freed.

However the subsequent plugins added(as reported by the plugin object manager) trigger double free, prevent this by taking a weak reference.

Fixes #371 (closed)

src/main.c

@@ -112,8 +112,9 @@ static void
 on_plugin_added (WpObjectManager * om, WpObject * p, WpInitTransition *self)
 {
   self->pending_plugins++;
-  wp_object_activate (p, WP_PLUGIN_FEATURE_ENABLED, NULL,
-      (GAsyncReadyCallback) on_plugin_activated, self);
+  wp_object_activate_closure (p, WP_PLUGIN_FEATURE_ENABLED, NULL,
+      g_cclosure_new_object (G_CALLBACK (on_plugin_activated),
+      G_OBJECT (self)));
 }
 
 static void