A few more ELABINELAB related changes. The ordering of interfaces

might different, as reported by the newnode MFS. At present, I need
the ordering (and thus, the iface names) to agree with the outer
emulab since that is how I request vlans to be setup. This is not
very pleasing, and I will probably have to change it to use MACs
instead. For now, reorder the new_interfaces based on what switchmac
(the proxy) tells us.