update_rrd_multi now supports null updates
update_rrd_multi now supports null updates

bbockelm/glideinWMS,holzman/glideinwms-old,bbockelm/glideinWMS,holzman/glideinwms-old,holzman/glideinwms-old,bbockelm/glideinWMS,bbockelm/glideinWMS