Don't remove delete_on_terminate volumes on a reschedule

When cleaning up volumes before a reschedule if delete_on_terminate is
True the volume would be deleted.  That's not the desired behavior so
the volume cleanup has been moved to take place when a build is aborted.

Change-Id: I142370c0555495b4d51736f4f6b8070a3c112a59
Closes-bug: #1336127
Update devref setup docs for latest libvirt on ubuntu

Adds instructions on how to enable the ubuntu cloud-archive
and update to the latest libvirt-dev from the icehouse repo.

This is needed to run unit tests in Juno if you're still on
ubuntu precise.

Change-Id: I8c93afdd72256b2bdc487e1413bdd570a6ea59e8
docs - Fix docstring issues

fix identation, add line before block comment ends, remove
extra colon (:) to remove ERROR(s) and WARNING(s)

Change-Id: Iabb09867bf6068da35251f35f9f689a623420692
Merge "Update devref setup docs for latest libvirt on ubuntu"
Merge "docs - Fix docstring issues"
Merge "Don't remove delete_on_terminate volumes on a reschedule"