add test to test neighbor mac change for ipv6 #287
Description
sudo ip -6 neigh change fc00::2 lladdr 58:bc:27:af:cc:bb dev Ethernet0
syslog
Sep 25 19:37:22.218138 str-s6000-acs-8 NOTICE orchagent: :- addNeighbor: Updated neighbor 58:bc:27:af:cc:dd on Ethernet0