Change apt_mk_version => mcp_version

   * Alligh all variables to one
   * Due mcp_version: ${_param:apt_mk_version}
     those change still bw compatible

Bug-relateted: PROD-24789 (PROD:24789)
Change-Id: I30b6fb0b1cb66c7d56dbb3a5e15c8bc9606405b5
diff --git a/defaults/debmirror.yml b/defaults/debmirror.yml
index 4376529..3995118 100644
--- a/defaults/debmirror.yml
+++ b/defaults/debmirror.yml
@@ -1,7 +1,7 @@
 parameters:
   _param:
     # Global
-    debmirror_mirrors_base_target_dir: "/srv/volumes/aptly/public/${_param:apt_mk_version}/"
+    debmirror_mirrors_base_target_dir: "/srv/volumes/aptly/public/${_param:mcp_version}/"
     # Per repo modificators
     mirror_mirantis_com_cassandra_xenial_force: False
     mirror_mirantis_com_ceph_luminous_xenial_force: False