param for specific repo release version (apt_mk)

Change-Id: Ief3c9e0e5ff0b5b068aba9ef45ef95c9d4152a02
diff --git a/linux/system/repo_local/mcp/contrail.yml b/linux/system/repo_local/mcp/contrail.yml
index 89a7236..3d02acf 100644
--- a/linux/system/repo_local/mcp/contrail.yml
+++ b/linux/system/repo_local/mcp/contrail.yml
@@ -1,13 +1,14 @@
 parameters:
   _param:
+    apt_mk_version: stable
     linux_repo_contrail_component: oc311
     contrail_repo_pin_priority: 200
-    apt_mk_version: stable
+    linux_system_repo_mcp_contrail_version: ${_param:apt_mk_version}
   linux:
     system:
       repo:
         mcp_opencontrail:
           refresh_db: ${_param:linux_repo_refresh_db}
-          source: "deb [arch=amd64] http://${_param:local_repo_url}/ubuntu-${_param:linux_system_codename}/ ${_param:apt_mk_version} ${_param:linux_repo_contrail_component}"
+          source: "deb [arch=amd64] http://${_param:local_repo_url}/ubuntu-${_param:linux_system_codename}/ ${_param:linux_system_repo_mcp_contrail_version} ${_param:linux_repo_contrail_component}"
           architectures: amd64
           key_url: "http://${_param:local_repo_url}/public.gpg"