Minor fix to createQuery method

Sonata Admin "List" pages were broken with the following fatal error:

*Call to undefined method Doctrine\ODM\PHPCR\Query\QueryBuilder::getQOMFactory()*

Have not run tests (can someone explain how I can do this), but tested working in cmf-sandbox project.

Please excuse me if this is not correct etiquette - I'm new to CMF dev.

Gez