Whenever your faction holds the Wintergrasp world battleground, all members of your faction gain the buff 'Essence of Wintergrasp' while in Northrend.
During Wrath of the Lich King, the Essence of Wintergrasp buff would allow the collection of Stone Keeper's Shards by performing certain actions - including the completion of Wrath of the Lich King dungeon instances.
In Cataclysm, Stone Keeper's Shards were converted into honor points, with the new honor/conquest system that was implemented. As a result of this change, any future instances where you would have previously gained Stone Keeper's Shards now result in you collecting a small quantity of honor points, which will most likely be how you got yours without doing any PvP.