Revert "Have DifferentialRevisionList return an ObjectBox if header is set"

This did bad things to dashboards, pulling it back until we have a more complete fix.

This reverts commit 468985c827.

Auditors: chad

src/applications/differential/controller/DifferentialRevisionViewController.php

@@ -778,7 +778,6 @@ final class DifferentialRevisionViewController extends DifferentialController {
     $user = $this->getRequest()->getUser();
 
     $view = id(new DifferentialRevisionListView())
-      ->setHeader(pht('Open Revisions Affecting These Files'))
       ->setRevisions($revisions)
       ->setUser($user);
 
@@ -786,7 +785,9 @@ final class DifferentialRevisionViewController extends DifferentialController {
     $handles = $this->loadViewerHandles($phids);
     $view->setHandles($handles);
 
-    return $view;
+    return id(new PHUIObjectBoxView())
+      ->setHeaderText(pht('Open Revisions Affecting These Files'))
+      ->appendChild($view);
   }