chown fernet keys to match container's keystone user and group

We used to use the host's keystone user and group. This is wrong since
we need to use the container's keystone user and group, which differs
from the host. This fixes that.

Change-Id: I0a64843c94bb173bb9e418bfca26927c1e2a123f
Closes-Bug: #1726727

playbooks/rotate-keys.yaml

@@ -11,6 +11,9 @@
 
   - name: Rotate fernet keys for keystone container
     block:
+      - set_fact:
+          keystone_base: /var/lib/config-data/puppet-generated/keystone
+
       - name: Remove previous fernet keys
         shell: rm -rf /var/lib/config-data/puppet-generated/keystone/etc/keystone/fernet-keys/*
         args:
@@ -18,11 +21,14 @@
 
       - name: Persist fernet keys to repository
         copy:
-          dest: "/var/lib/config-data/puppet-generated/keystone{{ item.key }}"
+          dest: "{{ keystone_base }}{{ item.key }}"
           content: "{{ item.value.content }}"
           mode: 0600
-          owner: keystone
-          group: keystone
+        with_dict: "{{ fernet_keys }}"
+        no_log: true
+
+      - name: Set permissions to match container's user
+        shell: chown --reference={{ keystone_base }}/etc/keystone/fernet-keys {{ keystone_base }}{{ item.key }}
         with_dict: "{{ fernet_keys }}"
         no_log: true