**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.

ConfigurationPtr users_config;                          
    InterserverIOHandler interserver_io_handler;            
    mutable std::optional<BackgroundSchedulePool> buffer_flush_schedule_pool; 
    mutable std::optional<BackgroundSchedulePool> schedule_pool;    
    mutable std::optional<BackgroundSchedulePool> distributed_schedule_pool; 
    mutable std::optional<BackgroundSchedulePool> message_broker_schedule_pool; 
    mutable ThrottlerPtr replicated_fetches_throttler; 
    mutable ThrottlerPtr replicated_sends_throttler; 
    MultiVersion<Macros> macros;                            
    std::unique_ptr<DDLWorker> ddl_worker;                  
    
    mutable std::unique_ptr<CompressionCodecSelector> compression_codec_selector;
    
    mutable std::shared_ptr<const DiskSelector> merge_tree_disk_selector;
    
    mutable std::shared_ptr<const StoragePolicySelector> merge_tree_storage_policy_selector;
    std::optional<MergeTreeSettings> merge_tree_settings;   
    std::optional<MergeTreeSettings> replicated_merge_tree_settings;   
    std::atomic_size_t max_table_size_to_drop = 50000000000lu; 
    std::atomic_size_t max_partition_size_to_drop = 50000000000lu; 
    String format_schema_path;                              
    ActionLocksManagerPtr action_locks_manager;             
    std::unique_ptr<SystemLogs> system_logs;                
    std::optional<StorageS3Settings> storage_s3_settings;   
    std::vector<String> warnings;                           
    
    MergeMutateBackgroundExecutorPtr merge_mutate_executor;
    OrdinaryBackgroundExecutorPtr moves_executor;
    OrdinaryBackgroundExecutorPtr fetch_executor;
    OrdinaryBackgroundExecutorPtr common_executor;