title: amqp queue_delete catch errors in async way
body: <p>I've just got started using pika(v 0.9.4) with Tornado (through the use of <code>pika.adapters.tornado_connection.TornadoConnection</code>) and I was wondering what's the appropriate way of catching errors when using, say: <code>queue_delete</code> for when the queue you're trying to delete doesn't exist. RabbitMQ raises AMQPError, but I am not sure how this can be handled in an async way.</p>
  
  <p>Anyone has any insights on this ?</p>