Description:
------------
When initializing stomp without a username it will segfault. See test script

Test script:
---------------
<?php
function mainAction() {
/* connection */
try {
$stomp = new \Stomp('tcp://localhost:61613');
} catch(\StompException $e) {
die('Connection failed: ' . $e->getMessage());
}

var_dump($stomp);
}

mainAction();
?>

Expected result:
----------------
Should not segfault