Add new python-jobs-linters template

Add a new template that can be used instead of python-jobs in
zuul/layout.yaml, it is the same as python-jobs but uses linters job
instead of pep8.

Change-Id: Ibea12fcb0078325c0457394f72ec0a799d3d8f69

zuul/layout.yaml

@@ -305,6 +305,20 @@ project-templates:
     post:
       - '{name}-branch-tarball-constraints'
 
+  # This is the same template as python-jobs but uses the new
+  # linters target instead of pep8.
+  - name: python-jobs-linters
+    check:
+      - 'gate-{name}-docs'
+      - 'gate-{name}-linters'
+      - 'gate-{name}-python27'
+    gate:
+      - 'gate-{name}-docs'
+      - 'gate-{name}-linters'
+      - 'gate-{name}-python27'
+    post:
+      - '{name}-branch-tarball'
+
   - name: grenade
     check:
       - 'gate-grenade-dsvm'