Hydrator not acception DateTime objects on @ODM\Date fields

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Exception: DateTime::__construct() expects parameter 1 to be string, object given
tests\Hydrators\DoctrineODMMongoDBTestsHydrationClosureUserHydrator.php:49
lib\Doctrine\ODM\MongoDB\Hydrator\HydratorFactory.php:428
tests\Doctrine\ODM\MongoDB\Tests\HydratorTest.php:31
Merge pull request #787 from stephandesouza/master

Hydrator not acception DateTime objects on @ODM\Date fields