**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.

}
    if (!all_in_zk)
        return CreateMergeEntryResult::MissingPart;
    ReplicatedMergeTreeLogEntryData entry;
    entry.type = LogEntry::MERGE_PARTS;
    entry.source_replica = replica_name;
    entry.new_part_name = merged_name;
    entry.new_part_uuid = merged_part_uuid;
    entry.new_part_type = merged_part_type;
    entry.merge_type = merge_type;
    entry.deduplicate = deduplicate;
    entry.deduplicate_by_columns = deduplicate_by_columns;
    entry.create_time = time(nullptr);
    for (const auto & part : parts)
        entry.source_parts.push_back(part->name);
    Coordination::Requests ops;
    Coordination::Responses responses;
    ops.emplace_back(zkutil::makeCreateRequest(
        fs::path(zookeeper_path) / "log/log-", entry.toString(),
        zkutil::CreateMode::PersistentSequential));
    ops.emplace_back(zkutil::makeSetRequest(
        fs::path(zookeeper_path) / "log", "", log_version)); 
    Coordination::Error code = zookeeper->tryMulti(ops, responses);
    if (code == Coordination::Error::ZOK)
    {
        String path_created = dynamic_cast<const Coordination::CreateResponse &>(*responses.front()).path_created;
        entry.znode_name = path_created.substr(path_created.find_last_of('/') + 1);
        ProfileEvents::increment(ProfileEvents::CreatedLogEntryForMerge);
        LOG_TRACE(log, "Created log entry {} for merge {}", path_created, merged_name);
    }