**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.

zkutil::ZooKeeperPtr & zookeeper, String part_name, LogEntry & entry, bool detach, bool throw_if_noop)
{
    LOG_TRACE(log, "Will try to insert a log entry to DROP_RANGE for part: " + part_name);
    auto part_info = MergeTreePartInfo::fromPartName(part_name, format_version);
    while (true)
    {
        ReplicatedMergeTreeMergePredicate merge_pred = queue.getMergePredicate(zookeeper);
        auto part = getPartIfExists(part_info, {MergeTreeDataPartState::Committed});
        if (!part)
        {
            if (throw_if_noop)
                throw Exception("Part " + part_name + " not found locally, won't try to drop it.", ErrorCodes::NO_SUCH_DATA_PART);
            return false;
        }
        if (merge_pred.hasDropRange(part->info))
        {
            if (throw_if_noop)
                throw Exception("Already has DROP RANGE for part " + part_name + " in queue.", ErrorCodes::PART_IS_TEMPORARILY_LOCKED);
            return false;
        }
        
        
        if (partIsAssignedToBackgroundOperation(part))