Room owners don't have admin rights

From codingteam@:

```
<rexim (room owner)>: $access
<horta hell> rexim: Общий
<tentacle the rapist (room admin)> $access
<horta hell> tentacle the rapist: Администратор
<ForNeVeR (you-know-who)> $access
<ForNeVeR> Общий
```

They all should actually be `RoomAdmin`s.