Link Local Address should be allowed to be set as router interface for IPv6 subnet

[Xu Han Peng]

Although Link Local address is allowed to be set as the gateway IP address of an IPv6 subnet when force_gateway_on_subnet is set to False, the following error will occur when attach the subnet to a neutron router:

neutron router-interface-add e911e39a-45e1-437f-bc5c-7c22b8c408d5 test_ipv6_subnet
400-{u'NeutronError': {u'message': u'Invalid input for operation: IP address fe80::2001:1 is not a valid IP for the defined subnet.', u'type': u'InvalidInput', u'detail': u''}}

This is because there is step to check if the gateway IP is inside the subnet when attaching the subnet to the router. This works for IPv4 but not IPv6 because IPv6 uses Link Local address ONLY to send RA.

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: master
Review: https://review.openstack.org/76125

[OpenStack Infra (hudson-openstack)]

Change abandoned by Salvatore Orlando (<email address hidden>) on branch: master
Review: https://review.openstack.org/76125

[Armando Migliaccio (armando-migliaccio)]

This bug is > 172 days without activity. We are unsetting assignee and milestone and setting status to Incomplete in order to allow its expiry in 60 days.

If the bug is still valid, then update the bug status.

[Launchpad Janitor (janitor)]

[Expired for neutron because there has been no activity for 60 days.]