conn_test: fix unparam warning
conn_test: fix unparam warning

Fix the following warning:

conn_test.go:341:51: `waitSignal` - `timeout` always receives `time.Second` (`1000000000`) (unparam)
func waitSignal(sigc <-chan *Signal, name string, timeout time.Duration) *Signal {
                                                  ^

by removing the timeout argument.

Signed-off-by: Kir Kolyshkin <3a017b8ddb3f9cf3e4a59978b004111bdeb97f08@gmail.com>

godbus/dbus