add Keystone region configuration

Change-Id: Icda5d46c296fcb2f7599dc9957baf15dd0925c54
diff --git a/metadata/service/control/single.yml b/metadata/service/control/single.yml
index df86a58..f52b8a6 100644
--- a/metadata/service/control/single.yml
+++ b/metadata/service/control/single.yml
@@ -18,6 +18,7 @@
         password: ${_param:mysql_cinder_password}
       identity:
         engine: keystone
+        region: RegionOne
         host: ${_param:single_address}
         port: 35357
         tenant: service