skip_unavailable_shards=1 makes 6 tries if a shard is unavailable

```
set skip_unavailable_shards=1;
select hostname(), * from cluster('{cluster}', system.one);

Connection failed at try №1,

Connection failed at try №2,

Connection failed at try №3,

Connection failed at try №1,

Connection failed at try №2,

Connection failed at try №3,
```

expected 3 try.