* Fixes for vagrant box builder in ubuntu-cpc LP: #1565985
* Remove extra packages added on 24 Jun 2016 except virtualbox-guest stuff
* Add cloud-init config to manage /etc/hosts for localhost
from a launchpad-buildd-like setup, which passes ARCH and SUBARCH in the
environment, because auto/config and auto/build both rely on this. So
don't scatter dpkg --print-architecture calls throughout, especially
when many of these are not cross-build-aware.
