Fix read the docs post job

The previous setup here was rejected by zuul as an invalid
configureation because trigger-readthedocs-webhook is defined as a final
job. Final jobs cannot be modified or parented (which is what the old
config was doing). Unfortunately, this prevented Zuul from running any
post jobs as it has to read the configuration for all jobs in a pipeline
as a whole.

We can fix this by feeding the trigger-readthedocs-webhook job the
necessary vars to run from project level vars. This doesn't modify the
job itself and only serves to add inputs to it.

Change-Id: Ibc3a62db4277aaf31956783aaef52be6f7a247b5

zuul.d/jobs.yaml

@@ -76,15 +76,6 @@
       serve_dir: /srv/iso
       serve_port: 8099
 
-- job:
-    name: airship-airshipctl-publish-docs
-    nodeset: airship-airshipctl-single-node
-    parent: trigger-readthedocs-webhook
-    run: playbooks/airship-airshipctl-build-docs.yaml
-    vars:
-      rtd_project_name: airship-airshipctl
-      rtd_webhook_id: 112688
-
 - job:
     name: airship-airshipctl-publish-image
     parent: airship-airshipctl-build-image

zuul.d/projects.yaml

@@ -11,6 +11,9 @@
 # limitations under the License.
 
 - project:
+    vars:
+      rtd_project_name: airship-airshipctl
+      rtd_webhook_id: 112688
     check:
       jobs:
         - airship-airshipctl-build-docs
@@ -27,6 +30,6 @@
         - airship-airshipctl-gate-test
     post:
       jobs:
-        - airship-airshipctl-publish-docs
+        - trigger-readthedocs-webhook
         - airship-airshipctl-publish-image
         - airship-airshipctl-upload-git-mirror