DNS Locations: when removing location remove it from servers first
    
    Locations should be removed from server by using server-mod during
    location-del (future patches will handle DNS records in server-mod)
    
    Referint plugin is configured to remove references of deleted locations.
    
    https://fedorahosted.org/freeipa/ticket/2008
    
    Reviewed-By: Petr Spacek <pspacek@redhat.com>
    Reviewed-By: Jan Cholasta <jcholast@redhat.com>