* fix a 'resource not found error' if the sqm service has been disabled and the dir '/var/run/sqm/available_qdiscs' not exist * inform the user about this issue and provide a button to enable & start the service Signed-off-by: Dirk Brenken <dev@brenken.org> (cherry picked from commit e76d9cc7673ffbebd8887bcfc14542c1269288e0)