Comment 4 for bug 1623261

Hello.
This source need to add after:

command = 'mkisofs -r -V "%s" -cache-inodes -J -l -b isolinux/isolinux.bin -c isolinux/boot.cat -no-emul-boot -boot-load-size 4 -boot-info-table -o "%s" .' % (
        model.custom_iso_image_volume_id, model.custom_iso_image_filepath)
    execute_asynchronous(thread, command, model.custom_live_iso_directory)