Merge remote branch 'craue/patch-4'

* craue/patch-4:
  typo

src/Symfony/Bridge/Doctrine/Validator/Constraints/UniqueEntityValidator.php

@@ -51,7 +51,7 @@ class UniqueEntityValidator extends ConstraintValidator
         $fields = (array)$constraint->fields;
 
         if (count($constraint->fields) == 0) {
-            throw new ConstraintDefinitionException("At least one field has to specified.");
+            throw new ConstraintDefinitionException("At least one field has to be specified.");
         }
 
         $em = $this->registry->getEntityManager($constraint->em);