ATLANTA — Colorado scored four runs in the third inning and pinch-hitter Ryan Raburn capped a big offensive performance for the Rockies with a ninth-inning grand slam in an 11-2 victory over the Atlanta Braves on Friday night. After averaging 2.7 runs in its last seven road games at San Francisco and the Los Angeles Dodgers, Colorado took advantage of baseball’s worst team. Dropping to 13-35 at home and 31-59 overall, the Braves rank last in the majors in runs scored and homers.