Mock evaluate function correctly
Mock evaluate function correctly

evaluate function needs VirtualNetworkST instance as first arg

Closes-bug: #1764496

Change-Id: I7c07c5f4fdb6c850cb6a2d2bb3c5b6c4d3261bd2

eonpatapon/contrail-controller,rombie/contrail-controller,rombie/contrail-controller,eonpatapon/contrail-controller,rombie/contrail-controller,eonpatapon/contrail-controller,rombie/contrail-controller,eonpatapon/contrail-controller,rombie/contrail-controller,eonpatapon/contrail-controller,eonpatapon/contrail-controller,rombie/contrail-controller,eonpatapon/contrail-controller,rombie/contrail-controller