test(net): skip usually failed test

re6st/tests/test_network/test_net.py

@@ -115,6 +115,7 @@ class TestNet(unittest.TestCase):
 
         self.assertTrue(wait_stable(nodes, 100), "ping test failed")
 
+    @unittest.skip("usually failed due to UPnP problem")
     def test_reboot_one_machine(self):
         """create a network demo, wait the net stable, reboot on machine,
         then test if network recover, this test seems always failed