message: don't write the tag of the epochs
diff: @@ -190,8 +190,6 @@ fn finish_epoch(storage: &storage::Storage, epoch_id : EpochId, writer : &mut st
  // TODO: should test that epoch <epoch_id - 1> exists.
  - storage::tag::write(&storage, &storage::tag::get_epoch_tag(epoch_id), &packhash[..]);
  -
  storage::epoch::epoch_create(&storage.config, &packhash, epoch_id);
  info!("=> pack {} written for epoch {} in {}", hex::encode(&packhash[..]),
  