**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.

{
    UInt64 res = 0;
    foreachCommittedParts([&res](auto & part) { res += part->getBytesOnDisk(); }, settings.select_sequential_consistency);
    return res;
}
void StorageReplicatedMergeTree::assertNotReadonly() const
{
    if (is_readonly)
        throw Exception(ErrorCodes::TABLE_IS_READ_ONLY, "Table is in readonly mode (zookeeper path: {})", zookeeper_path);
}
SinkToStoragePtr StorageReplicatedMergeTree::write(const ASTPtr & , const StorageMetadataPtr & metadata_snapshot, ContextPtr local_context)
{
    const auto storage_settings_ptr = getSettings();
    assertNotReadonly();
    const Settings & query_settings = local_context->getSettingsRef();
    bool deduplicate = storage_settings_ptr->replicated_deduplication_window != 0 && query_settings.insert_deduplicate;
    
    return std::make_shared<ReplicatedMergeTreeSink>(
        *this, metadata_snapshot, query_settings.insert_quorum,
        query_settings.insert_quorum_timeout.totalMilliseconds(),
        query_settings.max_partitions_per_insert_block,
        query_settings.insert_quorum_parallel,
        deduplicate,
        local_context);
}
bool StorageReplicatedMergeTree::optimize(