Handle the user accounts better (including neutering cloud-guest-utils
that mess with the kinds of auth (passwd) we want, and lock out accounts,
etc.

Also make sure to download stuff (like instance image cores) from the
boss.

Also, on aarch64, create the trusty-server image first, then the others.
Really, it's just the first non-kernel|initrd image *uploaded* into
openstack... it's still the last generated on disk ;)