message: Added safety for the existance of the MC track
diff: @@ -800,7 +800,9 @@ void AliAnalysisTaskPIDqa::FillTPCHistogramsNsigma(TList *sublist, Int_t scenari
  if (eventMC) {
  trackLabel=TMath::Abs(track->GetLabel());
  AliVTrack *mcTrack=(AliVTrack*)eventMC->GetTrack(trackLabel);
  + if(mcTrack)
  pdgCode=mcTrack->PdgCode();
  + //
  pdgCodeAbs=TMath::Abs(pdgCode);
  }
  @@ -1316,7 +1318,9 @@ void AliAnalysisTaskPIDqa::FillTRDHistogramsBasic(TList *sublistTRD, Int_t scena
  if (eventMC) {
  trackLabel=TMath::Abs(track->GetLabel());
  AliVTrack *mcTrack=(AliVTrack*)eventMC->GetTrack(trackLabel);
  + if(mcTrack)
  pdgCode=mcTrack->PdgCode();
  + //
  pdgCodeAbs=TMath::Abs(pdgCode);
  }
  