We were totally pumped when MAC announced plans to remix its classic Ruby Woo shades into RiRi Woo — a partnership with Rihanna, of course. “This post is for the MAC girls everywhere!!! My very first, very own, signature red lipstick #RiRiWoo is FINALLY AVAILABLE!!!! Get it online at Maccosmetics.com #MACRiRiWoo,” she tweeted on Thursday morning. Well,…