- Update list of supported releases
 - Make the fallback release trusty
 - Don't specify the compression algorithm (use auto-detection) so that
   people passing tarballs to the template don't see regressions.
Signed-off-by: Stéphane Graber <stgraber@ubuntu.com>
Acked-by: Serge E. Hallyn <serge.hallyn@ubuntu.com>