Set mcp_version to stable in trymcp

Change-Id: I8aa3ad662539e26c841c2e49c838635001ddc43b
diff --git "a/cluster_product/openstack/\173\173 cookiecutter.cluster_name \175\175/openstack/aio.yml" "b/cluster_product/openstack/\173\173 cookiecutter.cluster_name \175\175/openstack/aio.yml"
index 72a81e8..0bd2301 100755
--- "a/cluster_product/openstack/\173\173 cookiecutter.cluster_name \175\175/openstack/aio.yml"
+++ "b/cluster_product/openstack/\173\173 cookiecutter.cluster_name \175\175/openstack/aio.yml"
@@ -20,7 +20,7 @@
 - cluster.{{ cookiecutter.cluster_name }}.openstack
 parameters:
   _param:
-    mcp_version: {{ cookiecutter.mcp_version }}
+    mcp_version: stable
     openstack_control_address: {{ cookiecutter.aio_internal_address }}
   linux:
     system: