**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.

else
    {
        metadata_drop_lock->setAlreadyRemoved();
        completely_removed = true;
        LOG_INFO(logger, "Table {} was successfully removed from ZooKeeper", zookeeper_path);
    }
    return completely_removed;
}
/** Verify that list of columns and table storage_settings_ptr match those specified in ZK (/metadata).
  * If not, throw an exception.
  */
void StorageReplicatedMergeTree::checkTableStructure(const String & zookeeper_prefix, const StorageMetadataPtr & metadata_snapshot)
{
    auto zookeeper = getZooKeeper();
    ReplicatedMergeTreeTableMetadata old_metadata(*this, metadata_snapshot);
    Coordination::Stat metadata_stat;
    String metadata_str = zookeeper->get(fs::path(zookeeper_prefix) / "metadata", &metadata_stat);
    auto metadata_from_zk = ReplicatedMergeTreeTableMetadata::parse(metadata_str);
    old_metadata.checkEquals(metadata_from_zk, metadata_snapshot->getColumns(), getContext());
    Coordination::Stat columns_stat;
    auto columns_from_zk = ColumnsDescription::parse(zookeeper->get(fs::path(zookeeper_prefix) / "columns", &columns_stat));
    const ColumnsDescription & old_columns = metadata_snapshot->getColumns();
    if (columns_from_zk != old_columns)
    {
        throw Exception(ErrorCodes::INCOMPATIBLE_COLUMNS,
            "Table columns structure in ZooKeeper is different from local table structure. Local columns:\n"
            "{}\nZookeeper columns:\n{}", old_columns.toString(), columns_from_zk.toString());
    }
}
void StorageReplicatedMergeTree::setTableStructure(