unbreak exception handling

Summary: fix T10306

Test Plan: ¯\_(ツ)_/¯

Reviewers: chad, #blessed_reviewers, epriestley

Reviewed By: #blessed_reviewers, epriestley

Subscribers: Korvin

Maniphest Tasks: T10306

Differential Revision: https://secure.phabricator.com/D15229

src/applications/diffusion/controller/DiffusionServeController.php

@@ -100,7 +100,7 @@ final class DiffusionServeController extends DiffusionController {
           ->setResultCode(500)
           ->setProperties(
             array(
-              'exception.class' => $ex->getClass(),
+              'exception.class' => get_class($ex),
               'exception.message' => $ex->getMessage(),
             ));
       }