Description:
------------
Method AMQPQueue::ack() returns true even though connection is broken (ex. 
RabbitMQ stopped suddenly).

Tested with:

php5-amqp 0.3.1-1
php5-cli 5.3.3-7+squeeze3
php5-common 5.3.3-7+squeeze3
php5-suhosin 0.9.32.1-1

php5-amqp build with librabbitmq_1.0-1.20110925

Test script:
---------------
consumer.php:
<?php
include('config.php');

$amqp = new AMQPConnection($cfg['amqp']);
$amqp->connect();

$amqp_ex = new AMQPExchange($amqp);
$amqp_ex->declare($cfg['amqp']['exchange'],AMQP_EX_TYPE_TOPIC,AMQP_DURABLE);

$amqp_qu = new AMQPQueue($amqp);
$amqp_qu->declare($cfg['amqp']['queue'],AMQP_DURABLE); 
$amqp_qu->bind($cfg['amqp']['exchange'],'slave.#');

$msgs = $amqp_qu->consume(array('min' => 1,'max' => 10,'ack' => false));

sleep(10);
var_dump($amqp_qu->ack($msgs[0]['delivery_tag'])); ?>

Expected result:
----------------
Expected bool(false) or exception.

Actual result:
--------------
root@loc:~/php-amqp-bugs/ack# php -f consumer.php & sleep 1; 
/etc/init.d/rabbitmq-server stop
[1] 11592
Stopping rabbitmq-server: rabbitmq-server.
root@loc:~/php-amqp-bugs/ack# 
root@loc:~/php-amqp-bugs/ack# bool(true)