Fix an issue with rendering some commit hovercards

Summary: This logic wasn't quite right.

Test Plan: Hovered over a recognized commit, got a valid hovercard

Reviewers: chad

Reviewed By: chad

Differential Revision: https://secure.phabricator.com/D14925

src/applications/diffusion/engineextension/DiffusionHovercardEngineExtension.php

@@ -28,7 +28,7 @@ final class DiffusionHovercardEngineExtension
 
     $author_phid = $commit->getAuthorPHID();
     if ($author_phid) {
-      $author = $viewer->loadHandle($author)->renderLink();
+      $author = $viewer->renderHandle($author_phid);
     } else {
       $commit_data = $commit->loadCommitData();
       $author = phutil_tag('em', array(), $commit_data->getAuthorName());