BUGFIX/UPGRADE: Upgrading to 3.0: Filtering ProductQuestion correctly

git-svn-id: https://silverstripe-ecommerce.googlecode.com/svn/modules/ecommerce_product_questions/trunk@4585 950b781c-c544-efab-2f99-90083ee69683


git-svn-id: https://silverstripe-ecommerce.googlecode.com/svn/modules/ecommerce_product_questions/trunk@4589 950b781c-c544-efab-2f99-90083ee69683