Fix test_play_context fail with local config. (#17596)

If the current ansible enviroment has a config setup
that doesn't use 'smart' as the configured transport
test_play_context would fail when it assumes the
transport will be 'smart'.

test/units/playbook/test_play_context.py

@@ -53,7 +53,7 @@ class TestPlayContext(unittest.TestCase):
     def test_play_context(self):
         (options, args) = self._parser.parse_args(['-vv', '--check'])
         play_context = PlayContext(options=options)
-        self.assertEqual(play_context.connection, 'smart')
+        self.assertEqual(play_context.connection, C.DEFAULT_TRANSPORT)
         self.assertEqual(play_context.remote_addr, None)
         self.assertEqual(play_context.remote_user, None)
         self.assertEqual(play_context.password, '')