drop table in one of the backend sharding, check full @@metadata's result of consistent_in_data_nodes is 1,expect 0

[irene-coming]

• dble version：
  5.6.29-dble-9.9.9.9-02991f71759b437db3a6fc93343e2c9cd3c62c50-20200116025018
• preconditions ：
  no
• configs：

schema.xml

      <table name="test4" dataNode="dn1,dn2,dn3,dn4" rule="hash-four" cacheKey="id"/>

rule.xml

server.xml

• steps：
  step1. drop table at backend,eg dn1

drop table if exists test4

step2. reload @@metadata
step3. check full @@metadata

+
| schema  | table | reload_time         | table_structure                                                                                                                                 | consistent_in_data_nodes | consistent_in_memory |
+---------+-------+---------------------+-------------------------------------------------------------------------------------------------------------------------------------------------+--------------------------+----------------------+
| schema1 | test4 | 2020/01/17 11:01:29 | CREATE TABLE `test4` (
	`id` int(11) DEFAULT NULL,
	`name` char(1) DEFAULT NULL
) ENGINE = InnoDB CHARSET = latin1                              |                        1 |                    1 |

• expect result：
  1.step3, consistent_in_data_nodes value expect 0
• real result：
  1.
• supplements：
  1.found from autotest check_full_metadata.feature Scenario#5

[wjl1619]

verified on version: 5.6.29-dble-9.9.9.9-0bd119f7d9169b81808a54722958838718303940-20200205035800