**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 config;                                
    String tmp_path;                                        
    mutable VolumePtr tmp_volume;                           
    mutable VolumePtr backups_volume;                       
    mutable std::optional<EmbeddedDictionaries> embedded_dictionaries;    
    mutable std::optional<ExternalDictionariesLoader> external_dictionaries_loader;
    mutable std::optional<ExternalUserDefinedExecutableFunctionsLoader> external_user_defined_executable_functions_loader;
    mutable std::optional<ExternalModelsLoader> external_models_loader;
    ExternalLoaderXMLConfigRepository * external_models_config_repository = nullptr;
    scope_guard models_repository_guard;
    ExternalLoaderXMLConfigRepository * external_dictionaries_config_repository = nullptr;
    scope_guard dictionaries_xmls;
    ExternalLoaderXMLConfigRepository * user_defined_executable_functions_config_repository = nullptr;
    scope_guard user_defined_executable_functions_xmls;
#if USE_NLP
    mutable std::optional<SynonymsExtensions> synonyms_extensions;
    mutable std::optional<Lemmatizers> lemmatizers;
#endif
    String default_profile_name;                            
    String system_profile_name;                             
    String buffer_profile_name;                             
    std::unique_ptr<AccessControlManager> access_control_manager;
    mutable UncompressedCachePtr uncompressed_cache;        
    mutable MarkCachePtr mark_cache;                        
    mutable UncompressedCachePtr index_uncompressed_cache;  
    mutable MarkCachePtr index_mark_cache;                  
    mutable MMappedFileCachePtr mmap_cache; 
    ProcessList process_list;                               
    MergeList merge_list;                                   
    ReplicatedFetchList replicated_fetch_list;