Compatibility with WPML

Original fix by Rodolphe:
http://support.advancedcustomfields.com/forums/topic/relation-filter-with-category-in-wpml/

Say you create a group with a rule set to the category “CatA” that exist in english and is
translated as “CatA @fr” in french, the group will only appear on english posts set with
the english category, not on french posts set with the translated category “CatA @fr”.