message: For banning, consider only auction_delay eras.
diff: @@ -498,7 +498,7 @@ where
  }
  let slashed = self
  - .iter_past(era_id, self.bonded_eras())
  + .iter_past(era_id, self.banning_period())
  .filter_map(|old_id| key_blocks.get(&old_id).and_then(|bhdr| bhdr.era_end()))
  .flat_map(|era_end| era_end.equivocators.clone())
  .collect();
  @@ -536,6 +536,14 @@ where
  bonded_eras(&self.protocol_config)
  }
  + /// The number of past eras we have to check for faulty validators that will be banned in the
  + /// next era.
  + // TODO: This should just be `auction_delay`, but we need to guarantee we have enough
  + // eras.
  + fn banning_period(&self) -> u64 {
  + self.bonded_eras().min(self.protocol_config.auction_delay)
  + }
  +
  /// Returns the path to the era's unit hash file.
  fn unit_hash_file(&self, instance_id: &Digest) -> PathBuf {
  self.unit_hashes_folder.join(format!(
  @@ -858,7 +866,7 @@ where
  trace!(%seed, "the seed for {}: {}", era_id, seed);
  let slashed = self
  .era_supervisor
  - .iter_past_other(era_id, self.era_supervisor.bonded_eras())
  + .iter_past_other(era_id, self.era_supervisor.banning_period())
  .flat_map(|e_id| &self.era_supervisor.active_eras[&e_id].newly_slashed)
  .chain(&newly_slashed)
  .cloned()
  