Remove var override for docs publish job

This variable is no longer needed for the job (which is now final
so it doesn't work anyway).

Change-Id: Ibc2c70c223e5967551d097bb8b21eb8568849cb1
diff --git a/.zuul.yaml b/.zuul.yaml
index 1962611..2eadd4f 100644
--- a/.zuul.yaml
+++ b/.zuul.yaml
@@ -77,7 +77,5 @@
         - zuul-stream-functional
     post:
       jobs:
-        - publish-openstack-python-docs-infra:
-            vars:
-              afs_publisher_target: 'infra/zuul'
+        - publish-openstack-python-docs-infra
         - publish-openstack-python-branch-tarball