Rihanna is feeling irie about the holidays, mon! Though Christmas is more than two months away, the Barbados-born "Rude Boy" singer has issued a reggae-drenched version of the Yuletide classic "A Child Is Born." The song is included in the holiday compilation Now That's What I Call Christmas! Vol. 4, which is in stores today. The collection also includes renditions of "Merry Christmas Baby" by Sheryl Crow, "Have Yourself a Merry Little Christmas" by newly single songbird Christina Aguilera, and "Christmas Tree" by Lady Gaga, among other reinterpretations of the holiday songbook. Check out Riha...