CHCAGO — Derrel McDavid, R. Kelly’s former business manager and current co-defendant, has taken the stand in his own defense Wednesday in the final days of the disgraced singer’s Chicago federal trial. McDavid, wearing a gray suit and a light blue tie, was called to testify in the late morning, and his testimony could stretch into Thursday. McDavid had been slated to testify Tuesday, but the Dirksen U.S. Courthouse unexpectedly closed due to an unspecified “operational issue.” The delay means Kelly’s trial will almost certainly stretch into next week. McDavid, who faces charges along with Kell...