**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.

};
    for (const String & name : active_parts)
    {
        if (should_ignore_log_entry(created_get_parts, name, "Not fetching"))
            continue;
        LogEntry log_entry;
        if (are_restoring_replica)
        {
            LOG_DEBUG(log, "Obtaining checksum for path {}", name);
            
            
            log_entry.type = LogEntry::ATTACH_PART;
            MinimalisticDataPartChecksums desired_checksums;
            const fs::path part_path = fs::path(source_path) / "parts" / name;
            const String part_znode = zookeeper->get(part_path);
            if (!part_znode.empty())
                desired_checksums = ReplicatedMergeTreePartHeader::fromString(part_znode).getChecksums();
            else
            {
                String desired_checksums_str = zookeeper->get(part_path / "checksums");
                desired_checksums = MinimalisticDataPartChecksums::deserializeFrom(desired_checksums_str);
            }
            const auto [lo, hi] = desired_checksums.hash_of_all_files;
            log_entry.part_checksum = getHexUIntUppercase(hi) + getHexUIntUppercase(lo);
        }
        else
        {
            log_entry.type = LogEntry::GET_PART;
        }
        log_entry.source_replica = "";