a5790d5caa
Server.Serve() always returns a non-nil error. If it exits because the http server is closed, it will return ErrServerClosed. To differentiate the error, this patch changes to close the http server instead of the listener when the Service is deleted. Closing http server automatically closes the listener, there is no need to cache the listeners any more. Signed-off-by: Quan Tian <qtian@vmware.com>