message: Create a new scope for cs_main
  so that it is clear we need to hold cs_main throughout. Also add
  a comment beside IsBlockFinalized() to indicate we also need cs_main
  here as well.
diff: @@ -3925,6 +3925,7 @@ static bool FinalizeBlockInternal(CValidationState &state, CBlockIndex *pindex)
  }
  // Check that the request is consistent with current finalization.
  + {
  LOCK(cs_main); // for pindexFinalized
  if (pindexFinalized && !AreOnTheSameFork(pindex, pindexFinalized))
  {
  @@ -3936,13 +3937,14 @@ static bool FinalizeBlockInternal(CValidationState &state, CBlockIndex *pindex)
  // If we receive a block prior to the finalization point we may end up rolling back the current
  // finalization point. So we check here to see if the block is an ancestor of the finalized block index.
  - if (IsBlockFinalized(pindex))
  + if (IsBlockFinalized(pindex)) // also requires cs_main
  {
  return true;
  }
  // We have a valid candidate
  pindexFinalized = pindex;
  + }
  return true;
  }
  