tests: Adapted to changes in grl_plugin_registry_unregister_source.
tests: Adapted to changes in grl_plugin_registry_unregister_source.

kyoushuu/grilo,kyoushuu/grilo,kyoushuu/grilo,kyoushuu/grilo,GNOME/grilo,jasuarez/grilo,MathieuDuponchelle/grilo,MathieuDuponchelle/grilo,GNOME/grilo,MathieuDuponchelle/grilo,grilofw/grilo,jasuarez/grilo,jasuarez/grilo,grilofw/grilo,grilofw/grilo