I don't think it will really matter all that much. Your body probably won't need as much as it would when you're lifting, but over the course of 8-14 days (or however long your SD is), it's not going to make a difference whether you lower your protein intake a little or not.
Back when I still did SD's, I would usually just lower my total calories to maintenance levels (my maintenance clocks in at around 2800), and eat the same amount of protein I always eat. Seemed to work just fine.