Fix Freezer service config override issue

Freezer service configuration can't be override has describe here:
https://github.com/openstack/kolla-ansible/blob/master/doc/advanced-configuration.rst#L161

Kolla-ansible should look for files in /etc/kolla/config/ but it doesn't
take config files into account. This patch fix it.

Change-Id: Ia7d8d0892d13ba9785951a7b1291abb868fc714b
Closes-Bug: #1682404

ansible/roles/freezer/tasks/config.yml

@@ -39,10 +39,10 @@
       service_name: "{{ item.key }}"
     sources:
       - "{{ role_path }}/templates/freezer-api.conf.j2"
-      - "{{ node_config_directory }}/global.conf"
-      - "{{ node_config_directory }}/database.conf"
-      - "{{ node_config_directory }}/messaging.conf"
-      - "{{ node_config_directory }}/freezer.conf"
+      - "{{ node_custom_config }}/global.conf"
+      - "{{ node_custom_config }}/database.conf"
+      - "{{ node_custom_config }}/messaging.conf"
+      - "{{ node_custom_config }}/freezer.conf"
       - "{{ node_custom_config }}/freezer/{{ item.key }}.conf"
       - "{{ node_custom_config }}/freezer/{{ inventory_hostname }}/{{ item.key }}.conf"
     dest: "{{ node_config_directory }}/{{ item.key }}/freezer-api.conf"
@@ -60,7 +60,7 @@
 
 - name: Copying over existing policy.json
   template:
-    src: "{{ node_config_directory }}/freezer/policy.json"
+    src: "{{ node_custom_config }}/freezer/policy.json"
     dest: "{{ node_config_directory }}/{{ item.key }}/policy.json"
   register: freezer_policy_jsons
   when: