fix ps ut error;test=develop (#49867)

python/paddle/fluid/tests/unittests/test_dist_fleet_base.py

@@ -436,7 +436,7 @@ class TestFleetBase(unittest.TestCase):
             )
 
         if tr0_ret != 0 or tr1_ret != 0:
-            if is_listen_failed(ps0_err) or is_listen_failed(ps1_err):
+            if is_listen_failed(ps0_err_log) or is_listen_failed(ps1_err_log):
                 print("find parameter server port bind failed, skip the error")
                 tr0_ret, tr1_ret = 0, 0
             else: