**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.

{
    auto lock = getLock();
    if (settings_constraints_and_current_profiles)
        return settings_constraints_and_current_profiles;
    static auto no_constraints_or_profiles = std::make_shared<SettingsConstraintsAndProfileIDs>(getAccessControlManager());
    return no_constraints_or_profiles;
}
String Context::getCurrentDatabase() const
{
    auto lock = getLock();
    return current_database;
}
String Context::getInitialQueryId() const
{
    return client_info.initial_query_id;
}
void Context::setCurrentDatabaseNameInGlobalContext(const String & name)
{
    if (!isGlobalContext())
        throw Exception("Cannot set current database for non global context, this method should be used during server initialization",
                        ErrorCodes::LOGICAL_ERROR);
    auto lock = getLock();
    if (!current_database.empty())
        throw Exception("Default database name cannot be changed in global context without server restart",
                        ErrorCodes::LOGICAL_ERROR);
    current_database = name;
}
void Context::setCurrentDatabase(const String & name)