Jenkins for Juju GUI CI

[Gary Poster]

Hey Diogo.  We might be ready to start Jenkins integration.  We have a
few questions.

- We all have VPN credentials for the qa lab.  What do we do with them?
- What do we need to prepare for you to help us with the Jenkins
integration?
- Will it be easy for us to change the Jenkins integration?  Right now
we have a very basic story, but we already know of several simple
changes we want to make.  Will it be easy to gradually, incrementally
improve, without bothering you; or will it be better to make bigger
changes less frequently?

To give you an idea, here is the rough plan of what we would for our
first increment, assuming it is very easy to change.
- Install python-shelltoolbox, python-selenium, and juju on the Jenkins box
- Set up ~/.juju/environments.yaml with credentials and stuff for an
environment named "juju-gui-testing"
- Check out the juju-gui branch.  This provides a script, and is not
actually what is tested.
- Tell jenkins to run bin/test-charm with some environmental variables
set whenever the trunk changes.  We'd want to see the stdout from that
script, and it simply gives a standard exit code response on success and
failure.

In the future Jenkins would have some additional commands to run, but
that's all we'd want to get things going.

Thank you!

Gary