G4AtlasMTRunManager: initialize geometry before setting smartlessness.

If the detector geometry service is not initialized before retrieving
the logical volume store, the setting of the smartlessness will fail
silently. This commit moves the initialization beforehand. The new order
mirrors the order of the serial version, G4AtlasRunManager. If the
smartlessness is not set, Geant4's default value is used. This results
in a different voxelization, which was the cause of the safety
calculation discrepancy between serial and MT reported in ATLASSIM-3630.

Simulation/G4Atlas/G4AtlasAlg/src/G4AtlasMTRunManager.cxx

@@ -62,6 +62,16 @@ void G4AtlasMTRunManager::InitializeGeometry()
 {
   ATH_MSG_INFO("InitializeGeometry");
 
+  // Retrieve detector geo service
+  if (m_detGeoSvc.retrieve().isFailure()) {
+    ATH_MSG_ERROR("Could not retrieve the DetectorGeometrySvc");
+    G4ExceptionDescription description;
+    description << "InitializeGeometry: Failed to retrieve IDetectorGeometrySvc.";
+    G4Exception("G4AtlasMTRunManager", "CouldNotRetrieveDetGeoSvc",
+                FatalException, description);
+    abort(); // to keep Coverity happy
+  }
+
   // Set smartlessness
   G4LogicalVolumeStore *logicalVolumeStore = G4LogicalVolumeStore::GetInstance();
   const G4String muonSys("Muon::MuonSys");
@@ -77,16 +87,6 @@ void G4AtlasMTRunManager::InitializeGeometry()
     }
   }
 
-  // Retrieve detector geo service
-  if (m_detGeoSvc.retrieve().isFailure()) {
-    ATH_MSG_ERROR("Could not retrieve the DetectorGeometrySvc");
-    G4ExceptionDescription description;
-    description << "InitializeGeometry: Failed to retrieve IDetectorGeometrySvc.";
-    G4Exception("G4AtlasMTRunManager", "CouldNotRetrieveDetGeoSvc",
-                FatalException, description);
-    abort(); // to keep Coverity happy
-  }
-
   // Create/assign detector construction
   SetUserInitialization( m_detGeoSvc->GetDetectorConstruction() );
   if (userDetector) {