Hello everyone,

I've been trying to use the new prerelease system prior to releasing a
package to ROS Jade. The host machine is running 64bit Ubuntu Trusty and
it's been setup to run the prerelease tests based on the documentation on
ROS wiki.

It is not quite clear to me what this option do in the second step of
prerelease setup wizard: "Version of Ubuntu to test in". Does it specify
the host machine's Ubuntu distro or does it specify the base distro for the
pre-release environment (e.g. Docker image to download)? My intuition is it
should be the latter.

The issue is, whenever I generate a pre-release command for Ubuntu Vivid or
Utopic, the command fails with "ros_buildfarm.common.JobValidationError"
error. (Full output here:
https://gist.github.com/mani-monaj/e14629a83f82ace59cf4). Everything works
fine when I use Trusty as the distro.

- Mani