Only implement policy.json if an override is configured

With I6a61079da4d4f5080ee32d640144e6bdb14735fa merged there
is no longer a default policy.json file in the venv, so we
need to change how we implement the file, and should only do
so if there is a config override configured for it.

Change-Id: Ia4808a845dbb6d80c316a5e63fdc037ae1e2811e

tasks/neutron_post_install.yml

@@ -63,6 +63,13 @@
   notify:
     - Restart neutron services
 
+- name: Implement policy.json if there are overrides configured
+  copy:
+    content: "{{ neutron_policy_overrides | to_nice_json }}"
+    dest: "{{ neutron_conf_dir }}/policy.json"
+  when:
+    - neutron_policy_overrides != {}
+
 - name: Place api-paste.ini to the correct path in RedHat
   file:
     src: "/usr/share/neutron/api-paste.ini"

vars/main.yml

@@ -547,7 +547,3 @@ neutron_core_files:
     owner: "root"
     group: "{{ neutron_system_group_name }}"
     mode: "0640"
-  - tmp_f: "/tmp/policy.json.original"
-    target_f: "{{ neutron_conf_dir }}/policy.json"
-    config_overrides: "{{ neutron_policy_overrides }}"
-    config_type: "json"