Comment 2 for bug 1657170

We discussed this in today's ironic meeting [1] and it needs a spec. The API changes need to be described and it should be generalized so it doesn't make assumptions about the network interface being used.

We also have to remove assumptions from nova's virt-ironic driver [2] :-(

[1] http://eavesdrop.openstack.org/meetings/ironic/2017/ironic.2017-12-04-17.00.log.html#l-275
[2] https://github.com/openstack/nova/blob/878c44f0cff4f11b2a01e60019d79ccf5e5d707a/nova/virt/ironic/driver.py#L901-L904