fix Unknown table 'COLUMN_STATISTICS' error

clonedb.py

@@ -317,7 +317,7 @@ class CloningOperation:
 
         try:
             self.from_server.exec_query("SELECT COLUMN_NAME FROM information_schema.COLUMN_STATISTICS;")
-        except pymysql.err.OperationalError:
+        except pymysql.err.MySQLError:
             # fix the occasional 'Unknown table 'COLUMN_STATISTICS' in information_schema' bug
             base_cmd.append("--column-statistics=0")