message: error! -> warning!
  When a timestamp older than the earliest vote, we should just send a
  warning.
  This is because there could be network issues which cause this such as
  sender delays.
  See:
diff: @@ -223,7 +223,7 @@ impl<C: Context> ActiveValidator<C> {
  ) -> bool {
  let earliest_vote_time = self.earliest_vote_time(state);
  if timestamp < earliest_vote_time {
  - error!(%earliest_vote_time, %timestamp, "earliest_vote_time is greater than current time stamp");
  + warn!(%earliest_vote_time, %timestamp, "earliest_vote_time is greater than current time stamp");
  return false;
  };
  let vote = state.vote(vhash);
  