mysqldump will return error when config with backlist

[wjl1619]

• dble version：
  5.7.21-dble-3.21.06.0-9c90cabacaa870e85742d8e5014101661c014f4b-20210812071129
• preconditions ：
  no
• configs： user.xml

        <managerUser name="root" password="111111"/>
	<shardingUser name="test" password="111111" schemas="mytest" blacklist="blacklist1"/>
        <blacklist name="blacklist1">
          <property name="selectAllow">true</property>
        </blacklist>

• steps：
  step1. exec cmd

mysqldump -h10.186.65.78 -utest -P7131 -p111111   --default-character-set=utf8mb4 --master-data=2 --single-transaction --set-gtid-purged=off --hex-blob --databases mytest > mytest.sql

• expect result：
  1.execute success
• real result：
  1.

mysqldump -h10.186.65.78 -utest -P7131 -p111111   --default-character-set=utf8mb4 --master-data=2 --single-transaction --set-gtid-purged=off --hex-blob --databases mytest > export.sql
mysqldump: [Warning] Using a password on the command line interface can be insecure.
mysqldump: Couldn't execute 'FLUSH /*!40101 LOCAL */ TABLES': druid not support sql syntax, the reason is syntax error: syntax error, error in :'L */ TABLES, pos 30, line 1, column 31, token IDENTIFIER TABLES (1064)

• supplements：
  1.