OpticalTracker (RICH) test: fix unit conversion

Always use Geant4 units, as written out by ddsim root I/O

examples/OpticalTracker/scripts/test_energy_deposition.C

-#include "CLHEP/Units/SystemOfUnits.h"
-
 void test_energy_deposition(TString sim_file_name="sim.root") {
 
   // test requirements
-  const Double_t min_edep = 2*CLHEP::eV;
-  const Double_t max_edep = 5*CLHEP::eV;
+  const Double_t min_edep = 2 /*eV*/;
+  const Double_t max_edep = 5 /*eV*/;
 
   // get average energy deposition
   auto sim_file = new TFile(sim_file_name);
   auto t = (TTree*) sim_file->Get("EVENT");
   auto h = new TH1D("h","energy deposition",100,-1,20);
   t->Project("h","PFRICHHits.energyDeposit");
-  auto ave_edep = h->GetMean();
+  auto ave_edep = h->GetMean() * 1e6; // convert from MeV to eV
 
   // check if the average energy deposition is within expected range
   bool pass_test = ave_edep > min_edep && ave_edep < max_edep;
   std::cout << "TEST: " << (pass_test ? "passed" : "failed")
-    << " with average energy deposition = " << ave_edep/CLHEP::eV << " eV"
-    << " (expected in range (" << min_edep/CLHEP::eV << "," << max_edep/CLHEP::eV << ") eV)"
-    << std::endl;
+            << " with average energy deposition = " << ave_edep << " eV"
+            << " (expected in range (" << min_edep << "," << max_edep << ") eV)"
+            << std::endl;
 }