CBS now has two enemies: the first is, of course, Charlie Sheen, but the second one (as of Friday) is Bret Michaels. Last week, Bret filed a lawsuit against the network when his Rock of Ages performance at the 2009 Tony Awards resulted in a broken nose and stitches in his lip. When the incident initially occurred, Michaels’ representative — Joann Mignano — told the Associated Press that Michaels was hit in the head by a piece of scenery that was being lowered down, but clarified that the injuries her client…