Remove set but not used variables

Highlighted by clang-15 warnings such as:

warning: variable 'index' set but not used [-Wunused-but-set-variable]

Source/Modules/octave.cxx

@@ -1003,7 +1003,6 @@ public:
     List *baselist = Getattr(n, "bases");
     if (baselist && Len(baselist)) {
       Iterator b;
-      int index = 0;
       b = First(baselist);
       while (b.item) {
         String *bname = Getattr(b.item, "name");
@@ -1016,7 +1015,6 @@ public:
         Printf(base_class_names, "\"%s\",", bname_mangled);
         Printf(base_class, "0,");
         b = Next(b);
-        index++;
         Delete(bname_mangled);
       }
     }