Description:
------------
A memory leak appears in method AMQPQueue::declare.
If you need to check queue size in cycle it would be problem.

Test script:
---------------
$is_running = true;
while ($is_running) {
  $message_count = $queue->declare();
  echo "{$message_count} messages in queue";
  usleep(100000);
}

Expected result:
----------------
There should not be any memory leak

Actual result:
--------------
A memory leak appears