Add an experimental ironic partial upgrade test

This adds an experimental job to do partial upgrade testing of Ironic.
The goal of the job is to do a grenade test from juno to kilo without
upgrading Ironic, ensuring a kilo nova can successfully interface with
a Juno ironic for provisioning instances on nodes.

Change-Id: I1d91c9486e5879e62d4597b1647ae9752c729274

jenkins/jobs/devstack-gate.yaml

@@ -1365,6 +1365,39 @@
       - devstack-logs
       - console-log
 
+- job-template:
+    name: '{pipeline}-grenade-dsvm-partial-ironic{branch-designator}'
+    node: '{node}'
+
+    wrappers:
+      - build-timeout:
+          timeout: 130
+      - timestamps
+
+    builders:
+      - link-logs
+      - net-info
+      - devstack-checkout
+      - shell: |
+          #!/bin/bash -xe
+          export PYTHONUNBUFFERED=true
+          export DEVSTACK_GATE_TIMEOUT=120
+          export DEVSTACK_GATE_TEMPEST=0
+          export DEVSTACK_GATE_GRENADE=partial-ironic
+          export DEVSTACK_GATE_IRONIC=1
+          export DEVSTACK_GATE_NEUTRON=1
+          export DEVSTACK_GATE_VIRT_DRIVER=ironic
+          export TEMPEST_CONCURRENCY=2
+          export BRANCH_OVERRIDE={branch-override}
+          if [ "$BRANCH_OVERRIDE" != "default" ] ; then
+              export OVERRIDE_ZUUL_BRANCH=$BRANCH_OVERRIDE
+          fi
+          cp devstack-gate/devstack-vm-gate-wrap.sh ./safe-devstack-vm-gate-wrap.sh
+          ./safe-devstack-vm-gate-wrap.sh
+
+    publishers:
+      - devstack-logs
+      - console-log
 
 - job-template:
     name: '{pipeline}-grenade-dsvm-ironic-sideways{branch-designator}'
@@ -1762,6 +1795,7 @@
       - '{pipeline}-grenade-dsvm-partial-ncpu{branch-designator}'
       - '{pipeline}-grenade-dsvm-ironic{branch-designator}'
       - '{pipeline}-grenade-dsvm-ironic-sideways{branch-designator}'
+      - '{pipeline}-grenade-dsvm-partial-ironic{branch-designator}'
       - '{pipeline}-grenade-dsvm-neutron-sideways{branch-designator}'
       - '{pipeline}-tempest-dsvm-ironic-pxe_ssh{branch-designator}'
       - '{pipeline}-tempest-dsvm-ironic-pxe_ssh-postgres{branch-designator}'