Update the fileserver backends, requires that a salt.fileserver.Fileserver
    object be passed in

def fileserver_update(fileserver):
    '''
    Update the fileserver backends, requires that a salt.fileserver.Fileserver
    object be passed in
    '''
    try:
        if not fileserver.servers:
            log.error(
                'No fileservers loaded, the master will not be able to '
                'serve files to minions'
            )
            raise salt.exceptions.SaltMasterError('No fileserver backends available')
        fileserver.update()
    except Exception as exc:
        log.error(
            'Exception %s occurred in file server update', exc,
            exc_info_on_loglevel=logging.DEBUG
        )