message: Fix impact-parameter computation
diff: #include <TChain.h>
  #include "AliPIDResponse.h"
  #include "AliAnalysisTaskCheckAODTracks.h"
  +#include "AliNeutralTrackParam.h"
  /**************************************************************************
  @@ -1072,8 +1073,12 @@ void AliAnalysisTaskCheckAODTracks::UserExec(Option_t *)
  Double_t xv0=v0->Xv();
  Double_t yv0=v0->Yv();
  Double_t rv0=TMath::Sqrt(xv0*xv0+yv0*yv0);
  - Float_t d0v0[2], covd0v0[3];
  - v0->GetImpactParameters(d0v0, covd0v0);
  + Double_t d0v0[2], covd0v0[3];
  + const AliVTrack *trackVV0 = dynamic_cast<const AliVTrack*>(v0);
  + if(trackVV0){
  + AliNeutralTrackParam* trackV0 = new AliNeutralTrackParam(trackVV0);
  + trackV0->PropagateToDCA(vtTrc,magField,99999.,d0v0,covd0v0);
  + }
  if(ConvertAndSelectAODTrack(pTrack,vESD,magField)==kFALSE) continue;
  if(ConvertAndSelectAODTrack(nTrack,vESD,magField)==kFALSE) continue;
  