Add infra version of doc build job

Infra doesn't use constraints nor does it prevent branch publication.

Change-Id: I15fce2938222166e75984b75c568fa0fc083a8ee

playbooks/sphinx-docs/post-infra.yaml

@@ -0,0 +1,3 @@
+- hosts: all
+  roles:
+    - prepare-infra-docs-for-afs

zuul.yaml

@@ -65,6 +65,23 @@
       tox_envlist: venv
       tox_extra_args: -vv python setup.py build_sphinx
 
+- job:
+    name: build-openstack-infra-sphinx-docs
+    parent: tox-docs
+    description: |
+      Builds docuemtation using Sphinx per the OpenStack PTI but with
+      the Infra-specific publication prep applied. It then
+      collects the results into the log directory so that they can be
+      examined in their published form after a successful build.
+    run: playbooks/sphinx-docs/run
+    post-run: playbooks/sphinx-docs/post-infra
+    success-url: html/
+    roles:
+      - zuul: openstack-infra/zuul-jobs
+    vars:
+      tox_envlist: venv
+      tox_extra_args: -vv python setup.py build_sphinx
+
 - job:
     name: tox-py35-on-zuul
     parent: tox-py35