message: Rewrite one example of Result::map_err
  Closes:
  Approved by: metajack
diff: @@ -123,11 +123,9 @@ fn check_binary(cursor: &mut Cursor<&[u8]>) -> BinaryLoaderResult<u8> {
  } else {
  return Err(VMStatus::new(StatusCode::MALFORMED));
  }
  - if let Ok(count) = cursor.read_u8() {
  - Ok(count)
  - } else {
  - Err(VMStatus::new(StatusCode::MALFORMED))
  - }
  + cursor
  + .read_u8()
  + .map_err(|_| VMStatus::new(StatusCode::MALFORMED))
  }
  /// Reads all the table headers.
  