merged branch fixe/patch-3 (PR #3597)

Commits
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ed218bb Fixed an "Array to string conversion" warning when using PHP 5.4. Also affects Symfony2 master.

Discussion
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[Config] Fixed an "Array to string conversion" warning when using PHP 5.4

This also affects Symfony2 master

src/Symfony/Component/Config/Definition/ArrayNode.php

@@ -267,7 +267,7 @@ class ArrayNode extends BaseNode implements PrototypeNodeInterface
         if (count($value) && !$this->ignoreExtraKeys) {
             $msg = sprintf('Unrecognized options "%s" under "%s"', implode(', ', array_keys($value)), $this->getPath());
             $ex = new InvalidConfigurationException($msg);
-            $ex->setPath($this->getPath().'.'.reset($value));
+            $ex->setPath($this->getPath());
 
             throw $ex;
         }