fix timetruncate test case

tests/system-test/2-query/timetruncate.py

@@ -24,7 +24,8 @@ class TDTestCase:
         ]
         self.db_param_precision = ['ms','us','ns']
         self.time_unit = ['1w','1d','1h','1m','1s','1a','1u']
-        self.error_unit = ['1b','2w','2d','2h','2m','2s','2a','2u','1c','#1']
+        #self.error_unit = ['1b','2w','2d','2h','2m','2s','2a','2u','1c','#1']
+        self.error_unit = ['2w','2d','2h','2m','2s','2a','2u','1c','#1']
         self.ntbname = 'ntb'
         self.stbname = 'stb'
         self.ctbname = 'ctb'