Cleanup: replace Py_CLEAR with Py_DECREF in bpy.app modules

In this case, there is no benefit to using Py_CLEAR
as the value will never be NULL and can't be used later on.

source/blender/python/intern/bpy_app.c

@@ -216,7 +216,7 @@ static PyObject *make_app_info(void)
 #undef SetObjItem
 
   if (PyErr_Occurred()) {
-    Py_CLEAR(app_info);
+    Py_DECREF(app_info);
     return NULL;
   }
   return app_info;