**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.

{
    shared->interserver_scheme = scheme;
}
String Context::getInterserverScheme() const
{
    return shared->interserver_scheme;
}
void Context::setRemoteHostFilter(const Poco::Util::AbstractConfiguration & config)
{
    shared->remote_host_filter.setValuesFromConfig(config);
}
const RemoteHostFilter & Context::getRemoteHostFilter() const
{
    return shared->remote_host_filter;
}
UInt16 Context::getTCPPort() const
{
    auto lock = getLock();
    const auto & config = getConfigRef();
    return config.getInt("tcp_port", DBMS_DEFAULT_PORT);
}
std::optional<UInt16> Context::getTCPPortSecure() const
{
    auto lock = getLock();
    const auto & config = getConfigRef();
    if (config.has("tcp_port_secure"))
        return config.getInt("tcp_port_secure");
    return {};
}
void Context::registerServerPort(String port_name, UInt16 port)