Policy.json should be defined by user

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

Change-Id: I4db6b17ab1ff925aa20cd3565417a4b35ed4561e
diff --git a/tests/pillar/single.sls b/tests/pillar/single.sls
index 804c90f..6a2779c 100644
--- a/tests/pillar/single.sls
+++ b/tests/pillar/single.sls
@@ -34,3 +34,6 @@
       virtual_host: '/openstack'
     storage:
       engine: file
+    policy:
+      publicize_image: "role:admin"
+      add_member: