Add chdir for prepare-docs-for-afs

We need to be running out shell commands within the proper git src.

Change-Id: I9bb6bb85b1fc68cd475eddef38ed6bd11ee0f9dc
Signed-off-by: Paul Belanger <pabelanger@redhat.com>

roles/prepare-docs-for-afs/tasks/main.yaml

@@ -17,6 +17,7 @@
 
 - name: Rearrange publish directories
   args:
+    chdir: "{{ zuul_work_dir }}"
     executable: /bin/bash
   shell: |
     set -xe