manager: Don't load theme in constructor

Loading the theme can trigger calls to
fbd_feedback_manager_get_default() which then results in an endless look
as the object isn't fully initialized in constructed. Instead do
the setup in main() which has the advantage that the manager's life
cycle becomes more obvious too.

src/fbd-feedback-manager.c

@@ -439,8 +439,6 @@ fbd_feedback_manager_constructed (GObject *object)
 
   G_OBJECT_CLASS (fbd_feedback_manager_parent_class)->constructed (object);
 
-  fbd_feedback_manager_load_theme(self);
-
   g_signal_connect (self, "notify::profile", (GCallback)on_profile_changed, NULL);
 
   self->settings = g_settings_new (FEEDBACKD_SCHEMA_ID);