Parameterized linux_system_codename

Change-Id: Ic527bfa74b4caf7e0bb5d157bfae024f2cf53111
diff --git a/reclass/storage/system/openstack_dashboard_single.yml b/reclass/storage/system/openstack_dashboard_single.yml
index c2915d3..51e2d91 100644
--- a/reclass/storage/system/openstack_dashboard_single.yml
+++ b/reclass/storage/system/openstack_dashboard_single.yml
@@ -1,6 +1,7 @@
 parameters:
   _param:
     openstack_proxy_hostname: prx01
+    openstack_proxy_system_codename: trusty
   reclass:
     storage:
       node:
@@ -11,5 +12,5 @@
           - cluster.${_param:cluster_name}.openstack.dashboard
           params:
             salt_master_host: ${_param:reclass_config_master}
-            linux_system_codename: trusty
+            linux_system_codename: ${_param:openstack_proxy_system_codename}
             single_address: 172.16.10.121