**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.

}
void StorageReplicatedMergeTree::getClearBlocksInPartitionOps(
    Coordination::Requests & ops, zkutil::ZooKeeper & zookeeper, const String & partition_id, Int64 min_block_num, Int64 max_block_num)
{
    Strings blocks;
    if (Coordination::Error::ZOK != zookeeper.tryGetChildren(fs::path(zookeeper_path) / "blocks", blocks))
        throw Exception(zookeeper_path + "/blocks doesn't exist", ErrorCodes::NOT_FOUND_NODE);
    String partition_prefix = partition_id + "_";
    zkutil::AsyncResponses<Coordination::GetResponse> get_futures;
    for (const String & block_id : blocks)
    {
        if (startsWith(block_id, partition_prefix))
        {
            String path = fs::path(zookeeper_path) / "blocks" / block_id;
            get_futures.emplace_back(path, zookeeper.asyncTryGet(path));
        }
    }
    for (auto & pair : get_futures)
    {
        const String & path = pair.first;
        auto result = pair.second.get();
        if (result.error == Coordination::Error::ZNONODE)
            continue;
        ReadBufferFromString buf(result.data);
        const auto part_info = MergeTreePartInfo::tryParsePartName(result.data, format_version);
        if (!part_info || (min_block_num <= part_info->min_block && part_info->max_block <= max_block_num))
            ops.emplace_back(zkutil::makeRemoveRequest(path, -1));
    }
}
void StorageReplicatedMergeTree::clearBlocksInPartition(