Add job builder XML compare job

Change-Id: I228cf63639f5b173a99b003adac4134dba92b547
Reviewed-on: https://review.openstack.org/12287
Approved: James E. Blair <corvus@inaugust.com>
Reviewed-by: James E. Blair <corvus@inaugust.com>
Tested-by: Jenkins

modules/openstack_project/files/jenkins_job_builder/config/job-builder.yaml

@@ -0,0 +1,27 @@
+- job:
+    name: jenkins-job-builder-compare-xml
+    project-type: freestyle
+    concurrent: true
+    node: precise
+
+    wrappers:
+      - timeout:
+          timeout: 30
+          fail: true
+      - timestamps
+
+    triggers:
+      - zuul
+
+    logrotate:
+      daysToKeep: 1
+      numToKeep: -1
+      artifactDaysToKeep: -1
+      artifactNumToKeep: -1
+
+    builders:
+      - gerrit-git-prep
+      - shell: "./tools/run-compare-xml.sh"
+
+    publishers:
+      - console-log

modules/openstack_project/files/zuul/layout.yaml

@@ -59,6 +59,10 @@ jobs:
     voting: false
   - name: dev-zuul-coverage
     voting: false
+  - name: jenkins-job-builder-compare-xml
+    voting: false
+    failure-message: XML output has changed.
+    success-message: XML output is unchanged.
 
 
 projects:
@@ -147,6 +151,7 @@ projects:
   - name: openstack-ci/jenkins-job-builder
     check:
       - gate-jenkins-job-builder-merge
+      - jenkins-job-builder-compare-xml
     gate:
       - gate-jenkins-job-builder-merge