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/.kitchen.yml b/.kitchen.yml
index 14b02ce..6e38245 100644
--- a/.kitchen.yml
+++ b/.kitchen.yml
@@ -14,6 +14,10 @@
   formula: heat
   grains:
     noservices: True
+  dependencies:
+    - name: keystone
+      repo: git
+      source: https://github.com/salt-formulas/salt-formula-keystone
   state_top:
     base:
       "*":