Accusing Chicago officials of lacking political courage, U.S. Attorney General Jeff Sessions on a visit here Friday again blasted moves to reform police practices in the city.A 2015 agreement that requires officers to document incidents in which they stop and frisk people on the street “was a colossal mistake — an error of monumental proportions,” Sessions said in an address to the Chicago Crime Commission at the Union League Club of Chicago.After the decree went into effect on Jan. 1, 2016, he maintained …