Add neutron vpnaas configuration in integration tests.
Add neutron vpnaas configuration in integration tests.

They decided to remove the default once again because why not, it's
funny to break gates for no reason.

Change-Id: Iad096d134f66d625ff6d717e3be40dace66f6894
Closes-Bug: #1527499

openstack/heat,jasondunsmore/heat,steveb/heat,noironetworks/heat,cwolferh/heat-scratch,steveb/heat,openstack/heat,cwolferh/heat-scratch,dims/heat,noironetworks/heat,dims/heat,jasondunsmore/heat