R. Kelly in a high-profile child porn case, prosecutors will get a second crack at the disgraced Grammy winner.The 55-year-old R&B singer is slated to appear in federal court in Chicago on Monday to begin what in many ways is a do-over of his 2008 state trial, where shocking video he took of himself sexually assaulting and urinating on a 14-year-old girl was prosecutors’ “Exhibit 1.” However, this time around, the victim is expected to testify.