message: remove extra transaction in storage
diff: @@ -1760,8 +1760,8 @@ impl Storage {
  &self,
  block_hash: &BlockHash,
  ) -> Result<Option<BlockSignatures>, FatalStorageError> {
  - let mut tx = self.env.begin_ro_txn()?;
  - self.get_finality_signatures(&mut tx, block_hash)
  + let mut txn = self.env.begin_ro_txn()?;
  + self.get_finality_signatures(&mut txn, block_hash)
  }
  /// Retrieves single block header by height by looking it up in the index and returning it;
  @@ -1946,17 +1946,17 @@ impl Storage {
  /// emergency upgrade.
  fn get_sufficient_finality_signatures_by_hash<Tx: Transaction>(
  &self,
  - tx: &mut Tx,
  + txn: &mut Tx,
  block_hash: &BlockHash,
  ) -> Result<Option<BlockSignatures>, FatalStorageError> {
  // Needed to know what era the block was in, so that we can check what the validators were
  // and figure out if the signatures are sufficient.
  - let block_header = match self.read_block_header_by_hash(block_hash)? {
  + let block_header = match self.get_single_block_header(txn, block_hash)? {
  Some(header) => header,
  None => return Ok(None),
  };
  - self.get_sufficient_finality_signatures(tx, &block_header)
  + self.get_sufficient_finality_signatures(txn, &block_header)
  }
  /// Retrieves a deploy from the deploy store.
  @@ -1971,11 +1971,11 @@ impl Storage {
  &self,
  block_header_ids: &BlockHeadersBatchId,
  ) -> Result<Option<BlockHeadersBatch>, FatalStorageError> {
  - let mut tx = self.env.begin_ro_txn()?;
  + let mut txn = self.env.begin_ro_txn()?;
  let mut headers = Vec::with_capacity(block_header_ids.len() as usize);
  for block_height in block_header_ids.iter() {
  - match self.get_block_header_by_height_restricted(&mut tx, block_height, true)? {
  + match self.get_block_header_by_height_restricted(&mut txn, block_height, true)? {
  Some(block_header) => headers.push(block_header),
  None => {
  debug!(?block_height, "block header not found");
  