message: Remove unnecessary blockfile SetPos
  Nothing could have changed the position since we retrieved it a few statements earlier. This dates from commit
diff: @@ -4430,7 +4430,6 @@ void LoadExternalBlockFile(const CChainParams& chainparams, FILE* fileIn, FlatFi
  if (dbp)
  dbp->nPos = nBlockPos;
  blkdat.SetLimit(nBlockPos + nSize);
  - blkdat.SetPos(nBlockPos);
  std::shared_ptr<CBlock> pblock = std::make_shared<CBlock>();
  CBlock& block = *pblock;
  blkdat >> block;
  