Provide a smoother "update diff" web workflow

Summary:
Fixes T1102. If you don't use `arc`, the web workflow requires some extra needless steps when updating diffs.

Provide a more streamlined "Update Diff" workflow.

Test Plan: {F347750}

Reviewers: btrahan

Reviewed By: btrahan

Subscribers: epriestley

Maniphest Tasks: T1102

Differential Revision: https://secure.phabricator.com/D12131

src/applications/differential/controller/DifferentialController.php

@@ -2,18 +2,6 @@
 
 abstract class DifferentialController extends PhabricatorController {
 
-  protected function buildApplicationCrumbs() {
-    $crumbs = parent::buildApplicationCrumbs();
-
-    $crumbs->addAction(
-      id(new PHUIListItemView())
-        ->setHref($this->getApplicationURI('/diff/create/'))
-        ->setName(pht('Create Diff'))
-        ->setIcon('fa-plus-square'));
-
-    return $crumbs;
-  }
-
   public function buildSideNavView($for_app = false) {
     $viewer = $this->getRequest()->getUser();