Add allow-local-ssh-root to the packstack integration jobs

Packstack actually logs in to the nodes it wants to configure, even
if that node is localhost and an "all-in-one".

We could handle that logic from inside the job but since there is
a builder that does just that, let's leverage it.

Change-Id: Ibcfa11efd99692872c6ae439779f8e5dbc9bf03b

jenkins/jobs/packstack.yaml

@@ -6,6 +6,7 @@
       - print-template-name:
           template-name: "{template-name}"
       - link-logs
+      - allow-local-ssh-root
       - puppet-prepare-node
       - gerrit-git-prep
       - shell: |