Become root when fixing bridge logging

We are writing to /var/log/ansible which needs root perms. This was not
done and the writes failed. Fix that.

Change-Id: Ibe93519f2f549e85f0e238a210999c6281f42ce6

playbooks/zuul/run-production-playbook.yaml

@@ -53,6 +53,7 @@
         # bridge directly.
         - name: Rename playbook log on bridge
           when: not infra_prod_playbook_collect_log
+          become: yes
           copy:
             remote_src: yes
             src: "/var/log/ansible/{{ playbook_name }}.log"
@@ -60,6 +61,7 @@
 
         - name: Cleanup old playbook logs on bridge
           when: not infra_prod_playbook_collect_log
+          become: yes
           shell: |
             find /var/log/ansible -name '{{ playbook_name }}.log.*' -type f -mtime 30 -delete