Policy.json should be defined by user

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

Change-Id: I62dc05832a124b361a8d608326cbc6168af754c8
diff --git a/.kitchen.yml b/.kitchen.yml
index 8b89e35..d144018 100644
--- a/.kitchen.yml
+++ b/.kitchen.yml
@@ -24,6 +24,9 @@
     - name: linux
       repo: git
       source: https://github.com/salt-formulas/salt-formula-linux
+    - name: keystone
+      repo: git
+      source: https://github.com/salt-formulas/salt-formula-keystone
   state_top:
     base:
       "*":