Fix geant4 config script

Depending on an environment variable it can happen that a path contains a //.
In such a case the excution of the specified macro fails which is now fixed.

(cherry picked from commit 7f1b63bf)
(cherry picked from MR2034)

sim/transport/gconfig/g4Config.C

@@ -52,10 +52,12 @@ void Config()
 
   TString configm(gSystem->Getenv("CONFIG_DIR"));
   TString configm1 = configm + "/g4config.in";
+  configm1.ReplaceAll("//", "/");
   cout << " -I g4Config() using g4conf  macro: " << configm1 << endl;
 
   // set the common cuts
   TString cuts = configm + "/SetCuts.C";
+  cuts.ReplaceAll("//", "/");
   cout << "Physics cuts with script \n " << cuts.Data() << endl;
   Int_t cut = gROOT->LoadMacro(cuts.Data());
   if (cut == 0) gInterpreter->ProcessLine("SetCuts()");