Remove an unused variable

Summary: I was going to fix the variable name as it violates convention, but it is not used anyway.

Test Plan: N/A

Reviewers: #blessed_reviewers, epriestley

Reviewed By: #blessed_reviewers, epriestley

Subscribers: Korvin, epriestley

Differential Revision: https://secure.phabricator.com/D11139

src/applications/differential/lipsum/PhabricatorDifferentialRevisionTestDataGenerator.php

@@ -5,7 +5,6 @@ final class PhabricatorDifferentialRevisionTestDataGenerator
 
   public function generate() {
     $author = $this->loadPhabrictorUser();
-    $authorPHID = $author->getPHID();
 
     $revision = DifferentialRevision::initializeNewRevision($author);
     $revision->attachReviewerStatus(array());