message: Remove references to no longer present `indices`
diff: //! * Storing a deploy or block that already exists (same hash) is fine and will silently be
  //! accepted.
  //!
  -//! ## Indices
  -//!
  -//! The current implementation keeps only in-memory indices, which are not persisted, based upon the
  -//! estimate that they are reasonably quick to rebuild on start-up and do not take up much memory.
  -//!
  //! ## Errors
  //!
  //! The storage component itself is panic free and in general reports three classes of errors:
  @@ -1035,10 +1030,8 @@ impl Storage {
  block_hash,
  responder,
  } => {
  - let indices = self.indices.read()?;
  let result = self.get_sufficient_finality_signatures_by_hash(
  &mut self.env.begin_ro_txn()?,
  - &indices,
  &block_hash,
  )?;
  responder.respond(result).ignore()
  @@ -1912,7 +1905,6 @@ impl Storage {
  fn get_sufficient_finality_signatures_by_hash<Tx: Transaction>(
  &self,
  tx: &mut Tx,
  - indices: &Indices,
  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
  @@ -1922,7 +1914,7 @@ impl Storage {
  None => return Ok(None),
  };
  - self.get_sufficient_finality_signatures(tx, indices, &block_header)
  + self.get_sufficient_finality_signatures(tx, &block_header)
  }
  /// Retrieves a deploy from the deploy store.
  