TrackParticleTruthTPCnv: Update for change in event index handling.

TrackParticleTruthTPCnv: Update for change in event index handling.

HepMcParticleLink changed how MC event indices are handled.
Need to update the dummy link used for testing to correspond to this.
Fixes an assertion failure in the test in the debug build.

Reconstruction/TrackParticleTruthTPCnv/test/TrackParticleTruthCollectionCnv_p1_test.cxx

@@ -68,7 +68,8 @@ void test1 ATLAS_NOT_THREAD_SAFE (const std::vector<HepMC::GenParticlePtr>& genP
   std::cout << "test1\n";
   auto particle = genPartVector.at(0);
   // Create HepMcParticleLink outside of leak check.
-  HepMcParticleLink dummyHMPL(HepMC::barcode(particle),0,
+  HepMcParticleLink dummyHMPL(HepMC::barcode(particle),
+                              particle->parent_event()->event_number(),
                               HepMcParticleLink::IS_EVENTNUM,HepMcParticleLink::IS_BARCODE);
   assert(dummyHMPL.cptr()==particle);
   // Get proxy created outside of leak checking.