updating github.com/godbus/dbus to v4.1.0+incompatible

vendor/github.com/godbus/dbus/transport_unixcred_openbsd.go

@@ -0,0 +1,14 @@
+package dbus
+
+import "io"
+
+func (t *unixTransport) SendNullByte() error {
+	n, _, err := t.UnixConn.WriteMsgUnix([]byte{0}, nil, nil)
+	if err != nil {
+		return err
+	}
+	if n != 1 {
+		return io.ErrShortWrite
+	}
+	return nil
+}