Cut over to grizzly -> havana

* change BASE_RELEASE and TARGET_RELEASE in grenaderc
* remove work-arounds from devstack.localrc.target
* remove upgrade steps from the upgrade-* scripts
* change references to release names in variables to BASE_ and TARGET_
* fix check-sanity for proper credentials
* add teardown-javelin to make room for exercises

Fixes bug 1175340

Change-Id: Iff137039f4ac1d252c661fb945ce9d7b356e8f61
Merge branch 'havana' into dt-test