JOLIET — A hearing on a motion seeking to dismiss former Bolingbrook police sergeant Drew Peterson’s 2012 conviction for killing his third wife has been postponed until next month.Peterson’s motion to toss out his first-degree murder conviction in the death of Kathleen Savio was scheduled for a hearing on Friday, but the Will County Circuit Court Clerk’s office says the hearing has been postponed until Feb. 7.Recently, Judge Edward Burmila ruled that Peterson’s motion presented a “gist …