Avoid unnecessary vm interface update in VSP
Avoid unnecessary vm interface update in VSP

Update vm interface in VSP only in case of:
 - highest ipv4 or ipv6 address change
 - mac address change

Change-Id: I5e21d5ba022c41c8b956c5642a307ad377965bdb
Closes-Bug: OPENSTACK-2136

nuagenetworks/nuage-openstack-neutron,nuagenetworks/nuage-openstack-neutron