**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.

{
    
    fetcher.blocker.cancelForever();
    merger_mutator.merges_blocker.cancelForever();
    parts_mover.moves_blocker.cancelForever();
    restarting_thread.shutdown();
    background_operations_assignee.finish();
    part_moves_between_shards_orchestrator.shutdown();
    {
        auto lock = queue.lockQueue();
        
        
        
        queue.pull_log_blocker.cancelForever();
    }
    background_moves_assignee.finish();
    auto data_parts_exchange_ptr = std::atomic_exchange(&data_parts_exchange_endpoint, InterserverIOEndpointPtr{});
    if (data_parts_exchange_ptr)
    {
        getContext()->getInterserverIOHandler().removeEndpointIfExists(data_parts_exchange_ptr->getId(replica_path));
        
        data_parts_exchange_ptr->blocker.cancelForever();
        
        std::unique_lock lock(data_parts_exchange_ptr->rwlock);
    }
}
StorageReplicatedMergeTree::~StorageReplicatedMergeTree()