No DNS unless cloud-init=disabled if also netboot=nfs

Because cloud-init puts the interface in /etc/network/interfaces.d, the interplay between systemd-resolved and network-manager is blocked (network manager doesn't load the dns address into systemd-resolved.)

While the cloud-init interface has IPs and the routing table has routes -- no dns. no detail added for systemd-resolved.

And, Network Manager won't allow the interface to be started. Just a little broken network icon at the top.

Really bad when you do a casper install and the user is presented with a 'no network access' live cd.

Ver=plucky.