Provision deployment requirements for get-me-a-network
Provision deployment requirements for get-me-a-network

Neutron implemented an extension to allow users to automatically
provision a basic network topology to connect their instances.

One of the requirements for this feature is to be able to mark
an external network to be the one to be used for external
connectivity. Another requirement is subnetpools, which are
used to determine the IP space to allocate for private tenant
networks.

This patch codifies these requirements. The provisioning
needs to be  made conditional  based on the extensions
needed for this to work correctly.

Partially-implements: blueprint get-me-a-network

Change-Id: I43ce5d65e754f131f7ca1ce2088a397d266cf821

richliu/devstack,bswartz/devstack,Mahito/devstack,dirkmueller/devstack,samgoon/devstack,bigswitch/devstack,openstack-dev/devstack,bswartz/devstack,nawawi/openstack,noironetworks/devstack,Mahito/devstack,openstack-dev/devstack,group-policy/devstack,richliu/devstack,group-policy/devstack,samgoon/devstack,dirkmueller/devstack,bigswitch/devstack,dtroyer/devstack,nawawi/openstack,dtroyer/devstack,noironetworks/devstack