**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.

bool skip_sanity_checks = false;
    if (current_zookeeper && current_zookeeper->exists(replica_path + "/flags/force_restore_data"))
    {
        skip_sanity_checks = true;
        current_zookeeper->remove(replica_path + "/flags/force_restore_data");
        LOG_WARNING(log, "Skipping the limits on severity of changes to data parts and columns (flag {}/flags/force_restore_data).", replica_path);
    }
    else if (has_force_restore_data_flag)
    {
        skip_sanity_checks = true;
        LOG_WARNING(log, "Skipping the limits on severity of changes to data parts and columns (flag force_restore_data).");
    }
    loadDataParts(skip_sanity_checks);
    if (!current_zookeeper)
    {
        if (!attach)
        {
            dropIfEmpty();
            throw Exception("Can't create replicated table without ZooKeeper", ErrorCodes::NO_ZOOKEEPER);
        }
        
        LOG_ERROR(log, "No ZooKeeper: table will be in readonly mode.");
        is_readonly = true;
        return;
    }
    if (attach && !current_zookeeper->exists(zookeeper_path + "/metadata"))
    {
        LOG_WARNING(log, "No metadata in ZooKeeper for {}: table will be in readonly mode.", zookeeper_path);
        is_readonly = true;
        has_metadata_in_zookeeper = false;