Fix login screen backgroud path (#1777)
Fix login screen backgroud path (#1777)

OSGeo/OSGeoLive,astroidex/OSGeoLive,kalxas/OSGeoLive,kalxas/OSGeoLive,OSGeo/OSGeoLive,OSGeo/OSGeoLive,OSGeo/OSGeoLive,OSGeo/OSGeoLive,kalxas/OSGeoLive,OSGeo/OSGeoLive,astroidex/OSGeoLive,kalxas/OSGeoLive,kalxas/OSGeoLive,kalxas/OSGeoLive,OSGeo/OSGeoLive,astroidex/OSGeoLive,astroidex/OSGeoLive,astroidex/OSGeoLive,kalxas/OSGeoLive,astroidex/OSGeoLive