Fix coverity issue:

* CID 332682: Resource leak
* CID 350607: Resource leak
* CID 332677: Resource leak

src/Mod/TechDraw/App/AppTechDrawPy.cpp

@@ -1228,7 +1228,7 @@ private:
 
  PyObject* initModule()
 {
-    return (new Module)->module().ptr();
+    return Base::Interpreter().addModule(new Module);
 }
 
 } // namespace TechDraw