Merge branch '3.4' into 4.3

* 3.4:
  Fix inconsistent return points.
  [Security/Core] UserInterface::getPassword() can return null
  [Router] Fix TraceableUrlMatcher behaviour with trailing slash

Author: nicolas-grekas

CookieJar.php

@@ -60,6 +60,8 @@ public function get($name, $path = '/', $domain = null)
                 }
             }
         }
+
+        return null;
     }
 
     /**