Fixed PHP-1062: MongoID doesn't ignore invalid id

https://jira.mongodb.org/browse/PHP-1062


git-svn-id: https://svn.php.net/repository/phpdoc/en/trunk@333309 c90b9560-bf6c-de11-be94-00142212c4b1
Link to MongoId::isValid()


git-svn-id: https://svn.php.net/repository/phpdoc/en/trunk@333310 c90b9560-bf6c-de11-be94-00142212c4b1