param for specific repo release version (apt_mk)

Change-Id: Ief3c9e0e5ff0b5b068aba9ef45ef95c9d4152a02
diff --git a/linux/system/repo/mcp/extra.yml b/linux/system/repo/mcp/extra.yml
index 00de9ea..826969b 100644
--- a/linux/system/repo/mcp/extra.yml
+++ b/linux/system/repo/mcp/extra.yml
@@ -1,15 +1,16 @@
 parameters:
   _param:
     apt_mk_version: stable
+    linux_system_repo_mcp_extra_version: ${_param:apt_mk_version}
   linux:
     system:
       repo:
         mcp_extra:
-          source: "deb [arch=amd64] http://apt-mk.mirantis.com/${_param:linux_system_codename}/ ${_param:apt_mk_version} extra"
+          source: "deb [arch=amd64] http://apt-mk.mirantis.com/${_param:linux_system_codename}/ ${_param:linux_system_repo_mcp_extra_version} extra"
           architectures: amd64
           key_url: "http://apt-mk.mirantis.com/public.gpg"
           clean_file: true
           pin:
-          - pin: 'release a=${_param:apt_mk_version}'
+          - pin: 'release a=${_param:linux_system_repo_mcp_extra_version}'
             priority: 1100
             package: '*'