package-afs-centos: use synchronize flags for delete

It turns out if you read the documentation [1], it has an example for
synchronizing two directories with deletion and suggests using these
flags

[1] https://docs.ansible.com/ansible/latest/modules/synchronize_module.html#examples

Change-Id: Ib8aff5212d578668bf5073f28f08d12e7ddd3b1a

playbooks/package-afs-centos/post.yaml

@@ -24,5 +24,5 @@
         src: '{{ ansible_user_dir }}/rpmbuild/RPMS/x86_64/'
         dest: '{{ zuul.executor.work_root }}/artifacts/package-afs-centos7'
         mode: pull
-        rsync_opts:
-          - --delete
+        delete: true
+        recursive: true