message: Add query whether track and SPD vertex exist
diff: @@ -179,9 +179,9 @@ void AliFemtoDreamEvent::SetEvent(AliAODEvent *evt) {
  void AliFemtoDreamEvent::SetEvent(AliESDEvent *evt) {
  const AliVVertex *vtx = evt->GetPrimaryVertex();
  const AliVVertex* vtxSPD = evt->GetPrimaryVertexSPD();
  - fzVtxSPD = vtxSPD->GetZ();
  + fzVtxSPD = (vtxSPD) ? vtxSPD->GetZ() : vtx->GetZ();
  const AliESDVertex* vtxTrk = evt->GetPrimaryVertexTracks();
  - fzVtxTracks = vtxTrk->GetZ();
  + fzVtxTracks = (vtxTrk) ? vtxTrk->GetZ() : vtx->GetZ();
  AliESDVZERO *vZERO = evt->GetVZEROData();
  if (!vtx) {
  this->fHasVertex = false;
  