Copy Nova's policy.json to /etc/nova

Change-Id: I170e536331e617ea8984182d95616928f02a34a6
diff --git a/stack.sh b/stack.sh
index 66c8e93..d8720d9 100755
--- a/stack.sh
+++ b/stack.sh
@@ -1141,6 +1141,8 @@
 fi
 sudo chown `whoami` $NOVA_CONF_DIR
 
+cp -p $NOVA_DIR/etc/nova/policy.json $NOVA_CONF_DIR
+
 if is_service_enabled n-api; then
     # Use the sample http middleware configuration supplied in the
     # Nova sources.  This paste config adds the configuration required