**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 (entry.alter_version < metadata_version)
    {
        
        
        
        LOG_WARNING(log, "Attempt to update metadata of version {} "
                         "to older version {} when processing log entry {}: {}",
                         metadata_version, entry.alter_version, entry.znode_name, entry.toString());
        return true;
    }
    auto zookeeper = getZooKeeper();
    auto columns_from_entry = ColumnsDescription::parse(entry.columns_str);
    auto metadata_from_entry = ReplicatedMergeTreeTableMetadata::parse(entry.metadata_str);
    MergeTreeData::DataParts parts;
    
    Coordination::Requests requests;
    requests.emplace_back(zkutil::makeSetRequest(fs::path(replica_path) / "columns", entry.columns_str, -1));
    requests.emplace_back(zkutil::makeSetRequest(fs::path(replica_path) / "metadata", entry.metadata_str, -1));
    zookeeper->multi(requests);
    {