bug #5271 Fix nonexistent controller method (amansilla)

This PR was merged into the 2.3 branch.

Discussion
----------

Fix nonexistent controller method

| Q             | A
| ------------- | ---
| Doc fix?      | yes
| New docs?     | no
| Applies to    | 2.3
| Fixed tickets | #5272

Commits
-------

10a8b23 [#5272] Fix unexistent controller method

Author: wouterj

best_practices/security.rst

@@ -104,6 +104,10 @@ the security checks in PHP:
 
 .. code-block:: php
 
+    use Symfony\Component\Security\Core\Exception\AccessDeniedException;
+
+    // ...
+
     /**
      * @Route("/{id}/edit", name="admin_post_edit")
      */
@@ -117,7 +121,7 @@ the security checks in PHP:
         }
 
         if (!$post->isAuthor($this->getUser())) {
-            throw $this->createAccessDeniedException();
+            throw new AccessDeniedException();
         }
 
         // ...
@@ -192,6 +196,10 @@ Now, you can use the voter with the ``security.context`` service:
 
 .. code-block:: php
 
+    use Symfony\Component\Security\Core\Exception\AccessDeniedException;
+
+    // ...
+
     /**
      * @Route("/{id}/edit", name="admin_post_edit")
      */
@@ -200,7 +208,7 @@ Now, you can use the voter with the ``security.context`` service:
         $post = // query for the post ...
 
         if (!$this->get('security.context')->isGranted('edit', $post)) {
-            throw $this->createAccessDeniedException();
+            throw new AccessDeniedException();
         }
     }