Yet another new effort at getting neutron plus devstack working. This conf almost works.

The main learnings in this batch of experiments are:

• make sure there are no openvswitch leftovers in /etc
• use networks in local.conf that are entirely separate from existing networks on the machine
• booting a machine with --nic net-id=<uuid of the net named private> results in a machine I can eventually ssh to, but that host can't see out.