The change turns off the local nova metadata service and uses
endpoint data recieved from the quantum-network-service relation
to point the neutron metadata service at the nova metadata service
on the nova cloud controller for Queens+.
Depends-On: I5ad15ba782cb87b6fdb3c0941a6482d201670bff
Change-Id: I7037a20feac73f3a3f1ed1b8b1b70d0fa534bc46