**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 String & source_replica,
    const String & new_part_name,
    const DiskPtr & disk,
    const String & path)
{
    if (source_replica.empty())
    {
        LOG_INFO(log, "No active replica has part {} on shared storage.", new_part_name);
        return false;
    }
    const auto storage_settings_ptr = getSettings();
    auto metadata_snapshot = getInMemoryMetadataPtr();
    try
    {
        if (!fetchExistsPart(new_part_name, metadata_snapshot, fs::path(zookeeper_path) / "replicas" / source_replica, disk, path))
            return false;
    }
    catch (Exception & e)
    {
        if (e.code() == ErrorCodes::RECEIVED_ERROR_TOO_MANY_REQUESTS)
            e.addMessage("Too busy replica. Will try later.");
        tryLogCurrentException(log, __PRETTY_FUNCTION__);
        throw;
    }
    return true;
}
void StorageReplicatedMergeTree::executeDropRange(const LogEntry & entry)