Updated incorrect level-setting code to use setLevel(). (GH-16325)

diff --git a/Lib/test/test_logging.py b/Lib/test/test_logging.py
index dca744c..74ccf48 100644
--- a/Lib/test/test_logging.py
+++ b/Lib/test/test_logging.py
@@ -4315,7 +4315,7 @@
         logging._handlers.clear()
         logging._handlers.update(self.saved_handlers)
         logging._handlerList[:] = self.saved_handler_list
-        logging.root.level = self.original_logging_level
+        logging.root.setLevel(self.original_logging_level)
 
     def test_no_kwargs(self):
         logging.basicConfig()