Object, instead of a simple boolean should be returned by stop operation on mod_cluster

[standalone@127.0.0.1:9990 /] /subsystem=modcluster/proxy=default:stop()
{
    "outcome" => "success",
    "result" => {"session-draining-complete" => true}
}

[standalone@127.0.0.1:9990 /] /subsystem=modcluster/proxy=default:stop()
{
    "outcome" => "success",
    "result" => true
}