Fix handling of Empty Tag string in Stats Infra
Fix handling of Empty Tag string in Stats Infra

Change-Id: Iced3a500a850ac5a12c2e5f3c1385c86fa9b5736

DreamLab/contrail-controller,nischalsheth/contrail-controller,codilime/contrail-controller,eonpatapon/contrail-controller,vpramo/contrail-controller,eonpatapon/contrail-controller,nischalsheth/contrail-controller,hthompson6/contrail-controller,DreamLab/contrail-controller,srajag/contrail-controller,cloudwatt/contrail-controller,cloudwatt/contrail-controller,facetothefate/contrail-controller,srajag/contrail-controller,numansiddique/contrail-controller,facetothefate/contrail-controller,facetothefate/contrail-controller,vpramo/contrail-controller,tcpcloud/contrail-controller,codilime/contrail-controller,nischalsheth/contrail-controller,facetothefate/contrail-controller,reiaaoyama/contrail-controller,tcpcloud/contrail-controller,sajuptpm/contrail-controller,codilime/contrail-controller,tcpcloud/contrail-controller,reiaaoyama/contrail-controller,numansiddique/contrail-controller,rombie/contrail-controller,eonpatapon/contrail-controller,nischalsheth/contrail-controller,vmahuli/contrail-controller,vpramo/contrail-controller,hthompson6/contrail-controller,hthompson6/contrail-controller,sajuptpm/contrail-controller,vmahuli/contrail-controller,cloudwatt/contrail-controller,rombie/contrail-controller,DreamLab/contrail-controller,nischalsheth/contrail-controller,srajag/contrail-controller,sajuptpm/contrail-controller,codilime/contrail-controller,nischalsheth/contrail-controller,sajuptpm/contrail-controller,srajag/contrail-controller,numansiddique/contrail-controller,codilime/contrail-controller,reiaaoyama/contrail-controller,srajag/contrail-controller,codilime/contrail-controller,vmahuli/contrail-controller,eonpatapon/contrail-controller,reiaaoyama/contrail-controller,nischalsheth/contrail-controller,tcpcloud/contrail-controller,DreamLab/contrail-controller,DreamLab/contrail-controller,eonpatapon/contrail-controller,hthompson6/contrail-controller,tcpcloud/contrail-controller,vpramo/contrail-controller,sajuptpm/contrail-controller,rombie/contrail-controller,hthompson6/contrail-controller,eonpatapon/contrail-controller,cloudwatt/contrail-controller,vmahuli/contrail-controller,eonpatapon/contrail-controller,rombie/contrail-controller,cloudwatt/contrail-controller,sajuptpm/contrail-controller,numansiddique/contrail-controller,facetothefate/contrail-controller,rombie/contrail-controller,tcpcloud/contrail-controller,vpramo/contrail-controller,vmahuli/contrail-controller,rombie/contrail-controller,rombie/contrail-controller,numansiddique/contrail-controller,nischalsheth/contrail-controller,reiaaoyama/contrail-controller