**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_constraints_and_current_profiles->current_profiles;
}
std::vector<UUID> Context::getEnabledProfiles() const
{
    auto lock = getLock();
    return settings_constraints_and_current_profiles->enabled_profiles;
}
const Scalars & Context::getScalars() const
{
    return scalars;
}
const Block & Context::getScalar(const String & name) const
{
    auto it = scalars.find(name);
    if (scalars.end() == it)
    {
        
        
        throw Exception("Scalar " + backQuoteIfNeed(name) + " doesn't exist (internal bug)", ErrorCodes::BAD_ARGUMENTS);
    }
    return it->second;
}
const Block * Context::tryGetLocalScalar(const String & name) const