message: Fix index to have the CutOnChild selection working with Pythia8
diff: @@ -978,7 +978,7 @@ Int_t AliGenPythiaPlus::GenerateMB()
  }
  if(fCutOnChild && TMath::Abs(pdg) == fPdgCodeParticleforAcceptanceCut) {
  - Int_t mi = partCheck->GetFirstMother() - 1;
  + Int_t mi = (fPythia->Version() == 6) ? (partCheck->GetFirstMother() - 1) :(partCheck->GetFirstMother()) ;
  if(mi<0) continue;
  mother = (TParticle*)fParticles.At(mi);
  mpdg=TMath::Abs(mother->GetPdgCode());
  