Add barbican:server:database:host

The parameter is going to be moved to system level to
have a chance to redefine barbican DB server by value
had been passed dynamically.

Change-Id: I6d90718482c7e5b16f9b6c7fc488f5edbefc59a3
Related-PROD: PROD-21338 (PROD:21338)
diff --git a/barbican/server/cluster.yml b/barbican/server/cluster.yml
index d8b570c..81ee5af 100644
--- a/barbican/server/cluster.yml
+++ b/barbican/server/cluster.yml
@@ -9,3 +9,5 @@
       role: ${_param:openstack_node_role}
       identity:
         protocol: ${_param:cluster_internal_protocol}
+      database:
+        host: ${_param:openstack_database_address}