**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 (!next_task_callback.has_value())
        throw Exception(fmt::format("Next task callback is not set for query {}", getInitialQueryId()), ErrorCodes::LOGICAL_ERROR);
    return next_task_callback.value();
}
void Context::setReadTaskCallback(ReadTaskCallback && callback)
{
    next_task_callback = callback;
}
PartUUIDsPtr Context::getIgnoredPartUUIDs() const
{
    auto lock = getLock();
    if (!ignored_part_uuids)
        const_cast<PartUUIDsPtr &>(ignored_part_uuids) = std::make_shared<PartUUIDs>();
    return ignored_part_uuids;
}
AsynchronousInsertQueue * Context::getAsynchronousInsertQueue() const
{
    return shared->async_insert_queue.get();
}
void Context::setAsynchronousInsertQueue(const std::shared_ptr<AsynchronousInsertQueue> & ptr)
{
    using namespace std::chrono;
    if (std::chrono::milliseconds(settings.async_insert_busy_timeout_ms) == 0ms)
        throw Exception("Setting async_insert_busy_timeout_ms can't be zero", ErrorCodes::INVALID_SETTING_VALUE);
    shared->async_insert_queue = ptr;
}
void Context::initializeBackgroundExecutorsIfNeeded()