Add pillars with default policy configuration for OS services

PROD-34318

Change-Id: I46dee301c78450b2aa7a6430de1f3432756688d8
diff --git a/horizon/server/plugin/octavia.yml b/horizon/server/plugin/octavia.yml
index 576fd5b..b029b31 100644
--- a/horizon/server/plugin/octavia.yml
+++ b/horizon/server/plugin/octavia.yml
@@ -1,3 +1,5 @@
+classes:
+- system.defaults.openstack.policy.all
 parameters:
   horizon:
     server:
@@ -9,6 +11,5 @@
       policy:
         octavia:
           enabled: true
-          name: octavia_policy.json
-          source: file
-
+          source: pillar
+          pillar: ${_param:octavia_default_policy_${_param:openstack_version}}