**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.

Coordination::Stat metadata_stat;
                current_zookeeper->get(zookeeper_path + "/metadata", &metadata_stat);
                metadata_version = metadata_stat.version;
            }
            catch (Coordination::Exception & e)
            {
                if (!is_first_replica && e.code == Coordination::Error::ZNONODE)
                    throw Exception("Table " + zookeeper_path + " was suddenly removed.", ErrorCodes::ALL_REPLICAS_LOST);
                else
                    throw;
            }
            if (!is_first_replica)
                createReplica(metadata_snapshot);
        }
        catch (...)
        {
            
            dropIfEmpty();
            throw;
        }
    }
    else
    {
        
        String replica_metadata;
        const bool replica_metadata_exists = current_zookeeper->tryGet(replica_path + "/metadata", replica_metadata);
        if (!replica_metadata_exists || replica_metadata.empty())
        {
            
            other_replicas_fixed_granularity = checkFixedGranularityInZookeeper();