When building metadata with the use-fallback flag accept legacy icon names
When building metadata with the use-fallback flag accept legacy icon names

kalev/appstream-glib,superm1/appstream-glib,superm1/appstream-glib,hughsie/appstream-glib,kalev/appstream-glib,ximion/appstream-glib,ikeydoherty/appstream-glib,ximion/appstream-glib,mitya57/appstream-glib,hughsie/appstream-glib,ximion/appstream-glib,hughsie/appstream-glib,mitya57/appstream-glib,ikeydoherty/appstream-glib