Policy.json should be defined by user

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

Change-Id: I1accd9557cc241a55d5e898b9350b34e078b82a6
diff --git a/tests/pillar/server_cluster.sls b/tests/pillar/server_cluster.sls
index 0a8e0f5..c0330aa 100644
--- a/tests/pillar/server_cluster.sls
+++ b/tests/pillar/server_cluster.sls
@@ -51,3 +51,7 @@
       user: openstack
       password: password
       virtual_host: '/openstack'
+    policy:
+      deny_stack_user: 'not role:heat_stack_user'
+      'cloudformation:ValidateTemplate': 'rule:deny_stack_user'
+      'cloudformation:DescribeStackResource':