[Schema transformer] Retrun a correct set from VirtualNetworkST.delete
[Schema transformer] Retrun a correct set from VirtualNetworkST.delete

The methode VirtualNetworkST shoud always return a set() event if the
virtual network was already deleted.

Change-Id: Ib34bc255c3e63e70ecfa8e8c73f2786c60bd3845
Signed-off-by: Édouard Thuleau <685d42e881109fdae7d4fead4329459b04e3e152@cloudwatt.com>

codilime/contrail-controller,facetothefate/contrail-controller,codilime/contrail-controller,sajuptpm/contrail-controller,varunarya10/contrail-controller,Juniper/contrail-dev-controller,nischalsheth/contrail-controller,srajag/contrail-controller,eonpatapon/contrail-controller,vmahuli/contrail-controller,vpramo/contrail-controller,varunarya10/contrail-controller,varunarya10/contrail-controller,facetothefate/contrail-controller,reiaaoyama/contrail-controller,nischalsheth/contrail-controller,vmahuli/contrail-controller,varunarya10/contrail-controller,codilime/contrail-controller,rombie/contrail-controller,hthompson6/contrail-controller,nischalsheth/contrail-controller,hthompson6/contrail-controller,eonpatapon/contrail-controller,vmahuli/contrail-controller,eonpatapon/contrail-controller,cloudwatt/contrail-controller,sajuptpm/contrail-controller,Juniper/contrail-dev-controller,nischalsheth/contrail-controller,rombie/contrail-controller,numansiddique/contrail-controller,vpramo/contrail-controller,sajuptpm/contrail-controller,nischalsheth/contrail-controller,rombie/contrail-controller,srajag/contrail-controller,eonpatapon/contrail-controller,reiaaoyama/contrail-controller,codilime/contrail-controller,sajuptpm/contrail-controller,DreamLab/contrail-controller,vmahuli/contrail-controller,numansiddique/contrail-controller,cloudwatt/contrail-controller,codilime/contrail-controller,srajag/contrail-controller,cloudwatt/contrail-controller,cloudwatt/contrail-controller,nischalsheth/contrail-controller,tcpcloud/contrail-controller,tcpcloud/contrail-controller,eonpatapon/contrail-controller,codilime/contrail-controller,facetothefate/contrail-controller,tcpcloud/contrail-controller,numansiddique/contrail-controller,sajuptpm/contrail-controller,hthompson6/contrail-controller,Juniper/contrail-dev-controller,tcpcloud/contrail-controller,rombie/contrail-controller,hthompson6/contrail-controller,eonpatapon/contrail-controller,vpramo/contrail-controller,varunarya10/contrail-controller,reiaaoyama/contrail-controller,tcpcloud/contrail-controller,DreamLab/contrail-controller,rombie/contrail-controller,DreamLab/contrail-controller,vpramo/contrail-controller,nischalsheth/contrail-controller,sajuptpm/contrail-controller,DreamLab/contrail-controller,vpramo/contrail-controller,cloudwatt/contrail-controller,reiaaoyama/contrail-controller,numansiddique/contrail-controller,eonpatapon/contrail-controller,DreamLab/contrail-controller,Juniper/contrail-dev-controller,hthompson6/contrail-controller,srajag/contrail-controller,Juniper/contrail-dev-controller,vmahuli/contrail-controller,rombie/contrail-controller,srajag/contrail-controller,reiaaoyama/contrail-controller,facetothefate/contrail-controller,rombie/contrail-controller,numansiddique/contrail-controller,nischalsheth/contrail-controller,tcpcloud/contrail-controller,facetothefate/contrail-controller