**Describe the bug**
The ClickHouse client freezes when executing `ALTER TABLE` with `ADD COLUMN` and `MODIFY ORDER` on a table built using Replicated Versioned Collapsing Merge Tree engine.

**How to reproduce**
* ClickHouse client version 20.10.1.1.
Connecting to localhost:9000 as user default.
Connected to ClickHouse server version 20.10.1 revision 54440.

* `CREATE TABLE` statements
```
SHOW CREATE TABLE table0

┌─statement──────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────┐
│ CREATE TABLE default.table0
(
    `d` Date,
    `a` String,
    `b` UInt8,
    `x` String,
    `y` Int8,
    `version` UInt64,
    `sign` Int8 DEFAULT 1
)
ENGINE = ReplicatedVersionedCollapsingMergeTree('/clickhouse/tables/{shard}/table0', '{replica}', sign, version)
PARTITION BY y
ORDER BY d
SETTINGS index_granularity = 8192 │
└────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────┘

1 rows in set. Elapsed: 0.004 sec.
```

* Queries to run that lead to unexpected result
```
ALTER TABLE table0 ADD COLUMN order UInt32, MODIFY ORDER BY (d, order)
```
{
    auto host_port = global_context.getInterserverIOAddress();
    auto table_id = getStorageID();
    ReplicatedMergeTreeAddress res;
    res.host = host_port.first;
    res.replication_port = host_port.second;
    res.queries_port = global_context.getTCPPort();
    res.database = table_id.database_name;
    res.table = table_id.table_name;
    res.scheme = global_context.getInterserverScheme();
    return res;
}
ActionLock StorageReplicatedMergeTree::getActionLock(StorageActionBlockType action_type)
{
    if (action_type == ActionLocks::PartsMerge)
        return merger_mutator.merges_blocker.cancel();
    if (action_type == ActionLocks::PartsTTLMerge)
        return merger_mutator.ttl_merges_blocker.cancel();
    if (action_type == ActionLocks::PartsFetch)
        return fetcher.blocker.cancel();
    if (action_type == ActionLocks::PartsSend)
        return data_parts_exchange_endpoint ? data_parts_exchange_endpoint->blocker.cancel() : ActionLock();
    if (action_type == ActionLocks::ReplicationQueue)
        return queue.actions_blocker.cancel();
    if (action_type == ActionLocks::PartsMove)
        return parts_mover.moves_blocker.cancel();
    return {};
}
bool StorageReplicatedMergeTree::waitForShrinkingQueueSize(size_t queue_size, UInt64 max_wait_milliseconds)