After six hours of debate, which included a heated exchange between aldermen and a handful of activists in the gallery who were eventually escorted out by City Hall security, a slightly tweaked version of Mayor Rahm Emanuel’s police reform ordinance passed a joint committee in a 21-4 vote last night. Ald. Leslie Hairston (5), Ald. Chris Taliaferro (29) Ald. Nick Sposato (38), and Ald. Anthony Napolitano (41) voted against it.