Comment 5 for bug 1622002

The NoFilterMatched is actually because the grenade job doesn't automatically update dhcp.filters, I have a fix proposed there that I'll update with this bug info, https://review.openstack.org/#/c/371015/

There is still a fix required for neutron to catch when we don't have dhcp_release6, I'll update the existing patch based on multiple comments from Ihar and others.