Merge branch '4.3' into 4.4

* 4.3:
  cs fix
  Fix inconsistent return points.
  [Config] Add handling for ignored keys in ArrayNode::mergeValues.
  Fix inconsistent return points.
  [Security/Core] UserInterface::getPassword() can return null
  [Router] Fix TraceableUrlMatcher behaviour with trailing slash
  Revert "bug #33092 [DependencyInjection] Improve an exception message (fabpot)"

Author: Kyra Farrow

Response/CurlResponse.php

@@ -100,6 +100,8 @@ public function __construct(CurlClientState $multi, $ch, array $options = null,
 
                     return 1; // Abort the request
                 }
+
+                return null;
             });
         }