Invoke tox rpm-packaging-lint for PR checks

To have more than noop gating, we'd like to run the
"lint" tox environment on check and gate of each review.

Change-Id: I8f3a9817d29e2321f9eaf21f8e7974dea86e8960

jenkins/jobs/projects.yaml

@@ -6423,6 +6423,14 @@
       - python-jobs
       - pypi-jobs
 
+- project:
+    name: rpm-packaging
+    node: 'bare-precise || bare-trusty'
+
+    jobs:
+      - 'gate-{name}-tox-{envlist}':
+          envlist: lint
+
 - project:
     name: sahara
     node: 'bare-precise || bare-trusty'

zuul/layout.yaml

@@ -8620,7 +8620,10 @@ projects:
   - name: openstack/rpm-packaging
     template:
       - name: merge-check
-      - name: noop-jobs
+    check:
+      - gate-rpm-packaging-tox-lint
+    gate:
+      - gate-rpm-packaging-tox-lint
 
   - name: openstack/rpm-packaging-tools
     template: