**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();
    return settings;
}
void Context::setSettings(const Settings & settings_)
{
    auto lock = getLock();
    auto old_readonly = settings.readonly;
    auto old_allow_ddl = settings.allow_ddl;
    auto old_allow_introspection_functions = settings.allow_introspection_functions;
    settings = settings_;
    if ((settings.readonly != old_readonly) || (settings.allow_ddl != old_allow_ddl) || (settings.allow_introspection_functions != old_allow_introspection_functions))
        calculateAccessRights();
}
void Context::setSetting(const StringRef & name, const String & value)
{
    auto lock = getLock();
    if (name == "profile")
    {
        setCurrentProfile(value);
        return;
    }
    settings.set(std::string_view{name}, value);
    if (name == "readonly" || name == "allow_ddl" || name == "allow_introspection_functions")
        calculateAccessRights();
}
void Context::setSetting(const StringRef & name, const Field & value)