**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.

const IMergeTreeDataPart & part, DiskType disk_type) const
{
    String best_replica;
    zkutil::ZooKeeperPtr zookeeper = tryGetZooKeeper();
    if (!zookeeper)
        return best_replica;
    String zero_copy = fmt::format("zero_copy_{}", toString(disk_type));
    String zookeeper_part_node = fs::path(zookeeper_path) / zero_copy / "shared" / part.name;
    Strings ids;
    zookeeper->tryGetChildren(zookeeper_part_node, ids);
    Strings replicas;
    for (const auto & id : ids)
    {
        String zookeeper_part_uniq_node = fs::path(zookeeper_part_node) / id;
        Strings id_replicas;
        zookeeper->tryGetChildren(zookeeper_part_uniq_node, id_replicas);
        LOG_TRACE(log, "Found zookeper replicas for {}: {}", zookeeper_part_uniq_node, id_replicas.size());
        replicas.insert(replicas.end(), id_replicas.begin(), id_replicas.end());
    }
    LOG_TRACE(log, "Found zookeper replicas for part {}: {}", part.name, replicas.size());
    Strings active_replicas;
    
    
    active_replicas.reserve(replicas.size());
    for (const String & replica : replicas)
        if ((replica != replica_name) && (zookeeper->exists(fs::path(zookeeper_path) / "replicas" / replica / "is_active")))
            active_replicas.push_back(replica);