**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.

{
    assert(!metadata_transaction);
    assert(attach_existing || query_context.lock().get() == this);
    metadata_transaction = std::move(txn);
}
ZooKeeperMetadataTransactionPtr Context::getZooKeeperMetadataTransaction() const
{
    assert(!metadata_transaction || hasQueryContext());
    return metadata_transaction;
}
void Context::resetZooKeeperMetadataTransaction()
{
    assert(metadata_transaction);
    assert(hasQueryContext());
    metadata_transaction = nullptr;
}
PartUUIDsPtr Context::getPartUUIDs() const
{
    auto lock = getLock();
    if (!part_uuids)
        
        
        
        const_cast<PartUUIDsPtr &>(part_uuids) = std::make_shared<PartUUIDs>();
    return part_uuids;
}
ReadTaskCallback Context::getReadTaskCallback() const