Use PUBLIC_INTERFACE for public osops network

When neutron/quantum is not requested, nova network
is used. Nova network was setting the public
interface to use NEUTRON_INTERFACE which was
incorrectly setting the bridge & bridge_dev to use.
Add pubkey to authorized_keys if id_rsa already exists
Add RUN_FLAVOR_SETUP as an env var

This allows for the specification of keeping or
deleting all of the default nova flavors
Merge pull request #4 from metral/master

Bug fixes