fix compile error

src/SteppingAction.cc

@@ -38,7 +38,7 @@ void SteppingAction::UserSteppingAction(const G4Step* step) {
 
         //G4cout << "setting backscattering flag" << G4endl;
         trackSummary->update(fpSteppingManager->GetTrack());
-        trackSummary->getTrackSummary()->setBackScattering();
+        trackSummary->setBackScattering();
 
         // Suspend backscattering tracks to postpone them to the end of shower development.
         fpSteppingManager->GetTrack()->SetTrackStatus(fSuspend);