message: Fix incorrectly getting the parent of a block
diff: @@ -426,7 +426,7 @@ impl<I: NodeIdT, C: Context + 'static> HighwayProtocol<I, C> {
  }
  let opt_block = fork_choice.map(|bhash| self.highway.state().block(&bhash));
  let value = opt_block.map(|block| &block.value);
  - fork_choice = opt_block.map(|block| block.skip_idx[0]);
  + fork_choice = opt_block.and_then(|block| block.parent().cloned());
  value
  })
  }
  