Policy.json should be defined by user

User can override and add values to policy.json by creating flat
key-value structure under ceilometer:server:policy.

Change-Id: Ifeb2dbf54b0e32eb10a58f853a05fabf930a55a4
diff --git a/tests/pillar/server_cluster.sls b/tests/pillar/server_cluster.sls
index 0723a4d..52d5116 100644
--- a/tests/pillar/server_cluster.sls
+++ b/tests/pillar/server_cluster.sls
@@ -51,3 +51,6 @@
         enabled: true
         host: 127.0.0.1
         port: 8086
+      policy:
+        segregation: 'rule:context_is_admin'
+        'telemetry:get_resource':