The description of the handy haversack covers how the item works for the user if nothing about the user specifically changes how the haversack works. For average folks, "[r]etrieving any specific item from a [handy] haversack is a move action, but [doing so] does not provoke the attacks of opportunity that retrieving a stored item usually does."
However, a creature with the curse haunted isn't average. For such a creature "[r]etrieving any stored item from your gear requires a standard action, unless it would normally take longer." This makes it so the specific rules of the haunted curse override the general way in which the handy haversack functions. (For more about exception-based design in Pathfinder see here.)
For the handy haversack to function normally when used by the cursed creature, the haversack's description would have to say it was an exception to the haunted curse.