**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 (part->getBytesOnDisk() > max_source_part_size_for_mutation)
                        continue;
                    std::optional<std::pair<Int64, int>> desired_mutation_version = merge_pred.getDesiredMutationVersion(part);
                    if (!desired_mutation_version)
                        continue;
                    create_result = createLogEntryToMutatePart(
                        *part,
                        future_merged_part->uuid,
                        desired_mutation_version->first,
                        desired_mutation_version->second,
                        merge_pred.getVersion());
                    if (create_result == CreateMergeEntryResult::Ok)
                        break;
                }
            }
        }
    }
    catch (...)
    {
        tryLogCurrentException(log, __PRETTY_FUNCTION__);
    }
    if (!is_leader)
        return;
    if (create_result != CreateMergeEntryResult::Ok
        && create_result != CreateMergeEntryResult::LogUpdated)
    {
        merge_selecting_task->scheduleAfter(storage_settings_ptr->merge_selecting_sleep_ms);
    }
    else
    {