Use constant from neutron-lib
Use constant from neutron-lib

Follow up to https://review.openstack.org/636970.

TrivialChange

Change-Id: Ie0dce55b370a9942595ca205e560e6329609a2bf

mahak/neutron,openstack/neutron,openstack/neutron,mahak/neutron,openstack/neutron,mahak/neutron