IPV6_DHCP class for Generic image
This patch enables the IPV6_DHCP class for OpenStack, and use the -D LL option of dhclient (which makes dhclient send all the time the same DUID), so that an "openstack server rebuild" still gets an IPv6 address over DHCPv6 from dnsmasq (Closes: #991613).
Edited by Thomas Goirand