Fix few unused variable warnings

Source/Modules/go.cxx

@@ -4115,6 +4115,7 @@ private:
     String *name = Getattr(n, "sym:name");
     if (!name) {
       assert(is_ignored);
+      (void)is_ignored;
       name = Getattr(n, "name");
     }
 
@@ -6085,6 +6086,7 @@ private:
     }
     bool r = addSymbol(name, n, scope) ? true : false;
     assert(r);
+    (void)r;
     return true;
   }
 

Source/Modules/lua.cxx

@@ -1002,6 +1002,7 @@ public:
     //    REPORT("variableWrapper", n);
     String *lua_name = Getattr(n, "lua:name");
     assert(lua_name);
+    (void)lua_name;
     current[VARIABLE] = true;
     // let SWIG generate the wrappers
     int result = Language::variableWrapper(n);

Source/Modules/python.cxx

@@ -4875,6 +4875,7 @@ public:
 	      String *classname = Swig_class_name(parent);
 	      String *rclassname = Swig_class_name(getCurrentClass());
 	      assert(rclassname);
+	      (void)rclassname;
 
 	      String *parms = make_pyParmList(n, true, false, allow_kwargs);
 	      /* Pass 'self' only if using director */