title: Convert string to int in JMS Serializer
body: <p>I have a class with a field "price" type integer and the filed has an annotation @Type("integer"). When in the request the param "price" comes with a string (the user put a string instead of a integer), JMS Serializer (PHP do it too) transform this value (string value) to zero (0) and as zero is a integer the validator don't check this param and always is zero.</p>
  
  <p>Someone knows a config to JMS Serializer to don't convert a string to zero (0). Or any one else solutions.</p>
  
  <pre><code>/**
  * @JMS\Type("integer")
  * @var int
  */
  private $price;
  </code></pre>