Fix the windows buildbot permission error - close the fd of tempfile beffore unlinking

Lib/test/test_urllib.py

@@ -278,11 +278,12 @@ Content-Type: text/html; charset=iso-8859-1
     def test_file_notexists(self):
         fd, tmp_file = tempfile.mkstemp()
         tmp_fileurl = 'file://localhost/' + tmp_file.replace(os.path.sep, '/')
-
+        try:
             self.assertTrue(os.path.exists(tmp_file))
             with urlopen(tmp_fileurl) as fobj:
                 self.assertTrue(fobj)
-
+        finally:
+            os.close(fd)
             os.unlink(tmp_file)
         self.assertFalse(os.path.exists(tmp_file))
         with self.assertRaises(urllib.error.URLError):