Joseph Bisch
ddd3aed172
Switch to xenial for default suite
It can be confusing to new users for make-base-vm to create a lucid vm
by default, so switch to xenial, which is also a LTS release, but isn't
EOL yet. Using lucid with gitian-builder is broken anyway, because
lucid has been moved to old-releases.ubuntu.com since it is EOL and
gitian-builder doesn't support old-releases.ubuntu.com.