Deploy default policy files

At the moment our role does not account for provisionment of default
policy files for extra dashboards.

While they should not be required, it has been reported that absence
of such policy files results in unexpected behaviour. So let's symlink them
alike to how we do with regular policies.

Closes-Bug: #2055415
Change-Id: I683c12938fd4aa67304f564678514bc48bd86a79

tasks/horizon_post_install_source.yml

@@ -51,6 +51,21 @@
     use_regex: yes
   register: found_panels
 
+- name: Registering default policy files
+  find:
+    paths: |-
+      {% set policy_path = [] %}
+      {% for dashboard in found_dashboards.files %}
+      {%   for path in _dashboard_panels_location %}
+      {%     set _ = policy_path.append(dashboard.path + path + '/default_policies') %}
+      {%   endfor %}
+      {% endfor %}
+      {{ policy_path }}
+    patterns: ['^.*\.(json|yaml)$']
+    file_type: file
+    use_regex: yes
+  register: found_default_policy
+
 - name: Registering policy files
   find:
     paths: |-
@@ -66,6 +81,15 @@
     use_regex: yes
   register: found_policy
 
+- name: Link default policy files
+  file:
+    src: "{{ item.path }}"
+    dest: "{{ horizon_lib_dir }}/openstack_dashboard/conf/default_policies/{{ item.path | basename }}"
+    state: link
+  with_items: "{{ found_default_policy.files }}"
+  notify:
+    - Compile messages
+
 - name: Link policy files
   file:
     src: "{{ item.path }}"