Merge branch '4.3' into 4.4

* 4.3:
  Do not extend the new SF 4.3 ControllerEvent so we can make it final
  Backported return type violation bugfixes.
  [FrameworkBundle] Fix BrowserKit assertions to make them compatible with Panther

Author: nicolas-grekas

Encoder/EncoderAwareInterface.php

@@ -22,7 +22,7 @@ interface EncoderAwareInterface
      * If the method returns null, the standard way to retrieve the encoder
      * will be used instead.
      *
-     * @return string
+     * @return string|null
      */
     public function getEncoderName();
 }

User/User.php

@@ -71,6 +71,7 @@ public function getPassword()
      */
     public function getSalt()
     {
+        return null;
     }
 
     /**