Catched the Symfony exception in the XmlDecoder

The body decoders should return null when they cannot decode the
body, not throw an exception. This fixes the behavior change after
the switch to the Serializer component code.

Author: stof

Decoder/XmlDecoder.php

@@ -12,6 +12,7 @@
 namespace FOS\RestBundle\Decoder;
 
 use Symfony\Component\Serializer\Encoder\XmlEncoder;
+use Symfony\Component\Serializer\Exception\UnexpectedValueException;
 
 /**
  * Decodes XML data
@@ -34,6 +35,10 @@ public function __construct()
      */
     public function decode($data)
     {
-        return $this->encoder->decode($data, 'xml');
+        try {
+            return $this->encoder->decode($data, 'xml');
+        } catch (UnexpectedValueException $e) {
+            return null;
+        }
     }
 }