trivial: Fix a couple of small memory leaks
trivial: Fix a couple of small memory leaks

ximion/appstream-glib,hughsie/appstream-glib,ikeydoherty/appstream-glib,hughsie/appstream-glib,hughsie/appstream-glib,ximion/appstream-glib,ximion/appstream-glib,ikeydoherty/appstream-glib