bpo-43723: Fix deprecation error caused by thread.setDaemon() (GH-25361)

diff --git a/Lib/test/test_logging.py b/Lib/test/test_logging.py
index 452ba78..6179e28 100644
--- a/Lib/test/test_logging.py
+++ b/Lib/test/test_logging.py
@@ -849,7 +849,7 @@ def start(self):
         """
         self._thread = t = threading.Thread(target=self.serve_forever,
                                             args=(self.poll_interval,))
-        t.setDaemon(True)
+        t.daemon = True
         t.start()
 
     def serve_forever(self, poll_interval):
@@ -901,7 +901,7 @@ def start(self):
         """
         self._thread = t = threading.Thread(target=self.serve_forever,
                                             args=(self.poll_interval,))
-        t.setDaemon(True)
+        t.daemon = True
         t.start()
 
     def serve_forever(self, poll_interval):