**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.

{
    assertNotReadonly();
    if (!is_leader)
        throw Exception("DROP PART cannot be done on this replica because it is not a leader", ErrorCodes::NOT_A_LEADER);
    zkutil::ZooKeeperPtr zookeeper = getZooKeeper();
    LogEntry entry;
    dropPartImpl(zookeeper, part_name, entry, detach,  true);
    waitForLogEntryToBeProcessedIfNecessary(entry, query_context);
}
void StorageReplicatedMergeTree::dropPartition(const ASTPtr & partition, bool detach, ContextPtr query_context)
{
    assertNotReadonly();
    if (!is_leader)
        throw Exception("DROP PARTITION cannot be done on this replica because it is not a leader", ErrorCodes::NOT_A_LEADER);
    zkutil::ZooKeeperPtr zookeeper = getZooKeeper();
    LogEntry entry;
    String partition_id = getPartitionIDFromQuery(partition, query_context);
    bool did_drop = dropAllPartsInPartition(*zookeeper, partition_id, entry, query_context, detach);
    if (did_drop)
    {
        waitForLogEntryToBeProcessedIfNecessary(entry, query_context);
        cleanLastPartNode(partition_id);
    }
}
void StorageReplicatedMergeTree::truncate(