message: fix compilation on some operating systems / compiler versions
diff: @@ -371,7 +371,7 @@ void AliHLTTPCClusterStatComponent::TransformForward(int slice, int row, float p
  }
  }
  -static bool AliHLTTPCClusterStat_sorthelper(AliHLTTPCRawCluster& a, AliHLTTPCRawCluster& b)
  +static bool AliHLTTPCClusterStat_sorthelper(const AliHLTTPCRawCluster& a, const AliHLTTPCRawCluster& b)
  {
  if (a.GetPadRow() < b.GetPadRow()) return(true);
  if (a.GetPadRow() > b.GetPadRow()) return(false);
  