ErrorListener: Fixed wrong parameter being passed to the RuntimeException

[berni2288]

Fixed wrong exception throwing

PHP Error

Fatal error: Wrong parameters for Exception([string $exception [, long $code [, Exception $previous = NULL]]]) in
\lib\Gitlab\HttpClient\Listener\ErrorListener.php on line 60

Request that throwed the error

// Gitlab throwed an error because the source and target branch are the same
$project->createMergeRequest("samebranchname", "samebranchname", "Some text");

[m4tthumphrey]

Thanks!