Based on the following discussion:
http://lists.openstack.org/pipermail/openstack-dev/2017-September/121978.html
removeFixedIp action is deprecated, so instead of transforming its
notification, the instance.interface_detach versioned notification is
introduced.
Change-Id: Id4fa9eba59ef958ce514d9eb43346adf095b8b6e
Implements: blueprint versioned-notification-transformation-queens