**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.

const String & part_name, const String & zookeeper_path_, zkutil::ZooKeeper::Ptr zookeeper_)
{
    Strings replicas = zookeeper_->getChildren(fs::path(zookeeper_path_) / "replicas");
    
    std::shuffle(replicas.begin(), replicas.end(), thread_local_rng);
    for (const String & replica : replicas)
    {
        if (zookeeper_->exists(fs::path(zookeeper_path_) / "replicas" / replica / "parts" / part_name)
            && zookeeper_->exists(fs::path(zookeeper_path_) / "replicas" / replica / "is_active"))
            return fs::path(zookeeper_path_) / "replicas" / replica;
    }
    return {};
}
bool StorageReplicatedMergeTree::checkIfDetachedPartExists(const String & part_name)
{
    fs::directory_iterator dir_end;
    for (const std::string & path : getDataPaths())
        for (fs::directory_iterator dir_it{fs::path(path) / "detached/"}; dir_it != dir_end; ++dir_it)
            if (dir_it->path().filename().string() == part_name)
                return true;
    return false;
}
bool StorageReplicatedMergeTree::checkIfDetachedPartitionExists(const String & partition_name)