fix case

tests/system-test/0-others/user_control.py

@@ -169,7 +169,7 @@ class TDTestCase:
         login_except = False
         try:
             with taos_connect(user=user, passwd=passwd) as conn:
-                pass
+                cursor = conn.cursor()
         except BaseException:
             login_except = True
             cursor = None