designate: fix external backend deployment

The backend external tasks which utilize an existing bind9
installation require appropriate permissions to be able to
copy rndc config and key.

Closes-Bug: #1912063
Change-Id: Ie50228a26d635e3db82e41ec266ab820bf58938e
Signed-off-by: Daniel Meyerholt <dxm523@gmail.com>

ansible/roles/designate/tasks/backend_external.yml

@@ -4,6 +4,7 @@
     src: "{{ node_custom_config }}/designate/rndc.conf"
     dest: "{{ node_config_directory }}/{{ item.key }}/rndc.conf"
     mode: "0660"
+  become: true
   when:
     - designate_backend_external == 'bind9'
     - item.key in [ "designate-worker" ]
@@ -18,6 +19,7 @@
     src: "{{ node_custom_config }}/designate/rndc.key"
     dest: "{{ node_config_directory }}/{{ item.key }}/rndc.key"
     mode: "0660"
+  become: true
   when:
     - designate_backend_external == 'bind9'
     - item.key in [ "designate-worker" ]