I just tried this and found that `#validate_proposal_after_save` fails due to:

      elements["hawk-server"].each
        @logger.debug("checking #{n}")
        unless members.include? n
          node = NodeObject.find_node_by_name(n)
      ...

since in that case, `#find_node_by_name` fails on the cluster element.  Presumably we can just do

    server_elements, server_nodes, ha_enabled = role_expand_elements(role, "hawk-server")

once #15 is merged, and then iterate over `server_nodes` instead.