Move overrides to proper place

Change-Id: I18777620ecebbc36ed9fb9706624b378c3afae18
diff --git a/classes/cluster/virtual-mcp11-aio/infra/config.yml b/classes/cluster/virtual-mcp11-aio/infra/config.yml
index 9d60f84..c404233 100644
--- a/classes/cluster/virtual-mcp11-aio/infra/config.yml
+++ b/classes/cluster/virtual-mcp11-aio/infra/config.yml
@@ -1,9 +1,9 @@
 classes:
   - cluster.virtual-mcp11-aio
+  - cluster.overrides
 parameters:
   _param:
     linux_system_codename: xenial
-    mcp_version: testing
     linux_system_purge_repos: false
   linux:
     system: