appstream-builder: Do not abort the build if a non-package file is found
appstream-builder: Do not abort the build if a non-package file is found

Fixes: https://github.com/hughsie/appstream-glib/issues/8

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