**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 (!leader_election)
        return;
    
    
    leader_election->shutdown();
    if (is_leader)
    {
        LOG_INFO(log, "Stopped being leader");
        is_leader = false;
        merge_selecting_task->deactivate();
    }
    
    
    leader_election = nullptr;
}
ConnectionTimeouts StorageReplicatedMergeTree::getFetchPartHTTPTimeouts(ContextPtr local_context)
{
    auto timeouts = ConnectionTimeouts::getHTTPTimeouts(local_context);
    auto settings = getSettings();
    if (settings->replicated_fetches_http_connection_timeout.changed)
        timeouts.connection_timeout = settings->replicated_fetches_http_connection_timeout;
    if (settings->replicated_fetches_http_send_timeout.changed)
        timeouts.send_timeout = settings->replicated_fetches_http_send_timeout;
    if (settings->replicated_fetches_http_receive_timeout.changed)
        timeouts.receive_timeout = settings->replicated_fetches_http_receive_timeout;
    return timeouts;
}
bool StorageReplicatedMergeTree::checkReplicaHavePart(const String & replica, const String & part_name)