Fix a missing viewer after D5152

I think this one got mucked up in a merge or I didn't grep properly.

Auditors: vrana

src/applications/config/storage/PhabricatorConfigTransaction.php

@@ -78,7 +78,7 @@ final class PhabricatorConfigTransaction
     return parent::hasChangeDetails();
   }
 
-  public function renderChangeDetails() {
+  public function renderChangeDetails(PhabricatorUser $viewer) {
     $old = $this->getOldValue();
     $new = $this->getNewValue();
 
@@ -97,6 +97,7 @@ final class PhabricatorConfigTransaction
     }
 
     $view = id(new PhabricatorApplicationTransactionTextDiffDetailView())
+      ->setUser($viewer)
       ->setOldText($old_text)
       ->setNewText($new_text);
 

src/applications/transactions/storage/PhabricatorApplicationTransaction.php

@@ -325,7 +325,7 @@ abstract class PhabricatorApplicationTransaction
     return false;
   }
 
-  public function renderChangeDetails() {
+  public function renderChangeDetails(PhabricatorUser $viewer) {
     return null;
   }
 

src/applications/transactions/view/PhabricatorApplicationTransactionView.php

@@ -206,7 +206,7 @@ class PhabricatorApplicationTransactionView extends AphrontView {
         'style' => 'display: none',
         'class' => 'phabricator-timeline-change-details',
       ),
-      $xaction->renderChangeDetails());
+      $xaction->renderChangeDetails($this->getUser()));
 
     return array(
       $show_more,