devstack support for v2 nova/quantum integration

[dan wendlandt]

https://review.openstack.org/#/c/8916/4

adds a new version of quantum / Nova integration. This version require different flags than the older quantum-manager model.

we will need to update devstack to use these new flags (at least to start, this should be optional, and only enabled when quantum v2 is in use).

[Salvatore Orlando (salvatore-orlando)]

I reckon the change would basically consist of making sure the following flags are in place (from Yon's commit message on the gerrit review linked above):
network_api_class=nova.network.quantumv2.api.API
quantum_admin_username=admin
quantum_admin_password=password
quantum_admin_tenant_name=admin
quantum_admin_auth_url=http://localhost:5000/v2.0
quantum_auth_strategy=keystone
quantum_url=http://localhost:9696/

We do not want to remove network manager flags now.

[dan wendlandt (danwent)]

if we use quantum_auth_strategy=keystone, do we need to tweak the paste config in quantum.conf so that keystone middleware is inserted by default?

(Note: the paste config is soon going to be moving from quantum.conf to a separate api-paste.ini file, I believe).