**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.

std::optional<EphemeralLockInZooKeeper> & delimiting_block_lock, bool for_replace_range)
{
    
    
    Int64 left = 0;
    /** Let's skip one number in `block_numbers` for the partition being deleted, and we will only delete parts until this number.
      * This prohibits merges of deleted parts with the new inserted
      * Invariant: merges of deleted parts with other parts do not appear in the log.
      * NOTE: If you need to similarly support a `DROP PART` request, you will have to think of some new mechanism for it,
      *     to guarantee this invariant.
      */
    Int64 right;
    Int64 mutation_version;
    {
        auto zookeeper = getZooKeeper();
        delimiting_block_lock = allocateBlockNumber(partition_id, zookeeper);
        right = delimiting_block_lock->getNumber();
        
        
        
        mutation_version = MergeTreePartInfo::MAX_BLOCK_NUMBER;
    }
    if (for_replace_range)
    {