Use correct member to compare libvirt type For Havana: libvirt_type For Icehouse and above: libvirt.virt_type
Use correct member to compare libvirt type
For Havana: libvirt_type
For Icehouse and above: libvirt.virt_type

Change-Id: I9ec090fe32af48944479861899d082e89e8689d0

pupapaik/contrail-nova-vif-driver,eonpatapon/contrail-nova-vif-driver,vpramo/contrail-nova-vif-driver,JioCloud/contrail-nova-vif-driver,varunarya10/contrail-nova-vif-driver