**Describe the issue**
ClickHouse is unable to start up after upgrading from 20.8 to 21.8. 

There is a replicated table with `:` in zk path and it couldn't be loaded with:

`2021.09.15 03:49:58.435071 [ 633075 ] {} <Error> Application: DB::Exception: Unknown auxiliary ZooKeeper name '/test_prefix'. If it's required it can be added to the section <auxiliary_zookeepers> in config.xml: Cannot attach table `db1`.`table1` from metadata file /var/lib/clickhouse/metadata/db1/table1.sql from query ATTACH TABLE db1.table1 (`field1` String, `date` Date) ENGINE = ReplicatedMergeTree('/test_prefix:db1/{shard}/table1', '{replica}') PARTITION BY toMonth(date) PRIMARY KEY field1 ORDER BY field1 SETTINGS index_granularity = 8192: while loading database `db1` from path /var/lib/clickhouse/metadata/db1
`

**Expected behavior**
ClickHouse server is able to startup after upgrade without schema change. "test_prefix" in "/test_prefix:db1/{shard}/table1" is not interpreted as an auxiliary ZooKeeper name.

}
            else
            {
                if (zookeeper->exists(current_part_path))
                    throw Exception(ErrorCodes::LOGICAL_ERROR, "Part {} has empty header and does not have columns and checksums. "
                                                               "Looks like a bug.", current_part_path);
                LOG_INFO(log, "Not checking checksums of part {} with replica {} because part was removed from ZooKeeper", part_name, replica);
                continue;
            }
        }
        else
        {
            replica_part_header = ReplicatedMergeTreePartHeader::fromString(part_zk_str);
        }
        if (replica_part_header.getColumnsHash() != local_part_header.getColumnsHash())
        {
            
            
            
            throw Exception(ErrorCodes::CHECKSUM_DOESNT_MATCH, "Part {} from {} has different columns hash", part_name, replica);
        }
        replica_part_header.getChecksums().checkEqual(local_part_header.getChecksums(), true);
        if (replica == replica_name)
            has_been_already_added = true;
        
        
        if (absent_replicas_paths)
        {
            absent_replicas_paths->clear();
            break;