Add a ci test for teardown operations

[larsks]

We're currently running teardown tasks against a "clean" system, so there's nothing to tear down. We should have job that:

• Gets as far as starting the undercloud
• Cleans everything up (libvirt/teardown and envrionment/teardown)
• Re-provisions and boots the undercloud

[larsks]

If we add a teardown test, maybe we can remove some of the superfluous teardown roles from the minimal.yml playbook so that it's a little bit more of a useful example.

[larsks]

Can we feed one job the output of another jenkins job? That is, can we configure a teardown test that runs after one of the deploy gate tests and acts on that environment?

[trown]

I think we can track this as part of https://bugs.launchpad.net/tripleo-quickstart/+bug/1570289