**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.

#include <Common/Throttler.h>
#include <Common/thread_local_rng.h>
#include <Common/FieldVisitorToString.h>
#include <Common/getMultipleKeysFromConfig.h>
#include <Coordination/KeeperDispatcher.h>
#include <Compression/ICompressionCodec.h>
#include <Core/BackgroundSchedulePool.h>
#include <Formats/FormatFactory.h>
#include <Databases/IDatabase.h>
#include <Storages/IStorage.h>
#include <Storages/MarkCache.h>
#include <Storages/MergeTree/MergeList.h>
#include <Storages/MergeTree/ReplicatedFetchList.h>
#include <Storages/MergeTree/MergeTreeData.h>
#include <Storages/MergeTree/MergeTreeSettings.h>
#include <Storages/CompressionCodecSelector.h>
#include <Storages/StorageS3Settings.h>
#include <Disks/DiskLocal.h>
#include <TableFunctions/TableFunctionFactory.h>
#include <Interpreters/ActionLocksManager.h>
#include <Interpreters/ExternalLoaderXMLConfigRepository.h>
#include <Core/Settings.h>
#include <Core/SettingsQuirks.h>
#include <Access/AccessControlManager.h>
#include <Access/ContextAccess.h>
#include <Access/EnabledRolesInfo.h>
#include <Access/EnabledRowPolicies.h>
#include <Access/QuotaUsage.h>
#include <Access/User.h>
#include <Access/Credentials.h>