message: Return false from record_entry if no WAL.
diff: @@ -1105,7 +1105,8 @@ impl<C: Context + 'static> SimpleConsensus<C> {
  /// node shuts down.
  fn record_entry(&mut self, entry: &Entry<C>) -> bool {
  match self.write_wal.as_mut().map(|ww| ww.record_entry(entry)) {
  - None | Some(Ok(())) => true,
  + None => false,
  + Some(Ok(())) => true,
  Some(Err(err)) => {
  self.active_validator = None;
  self.write_wal = None;
  