SAN FRANCISCO — The Giants were in need of a slump buster, and through the first two games of this series, the Colorado Rockies have provided just that. So, no different than last year. Sure, the Giants took the final two games of their previous series with the Cardinals, but they are officially on a roll after two blowout wins in their first two games with the Rockies this season. The 9-2 win Tuesday night extended their unbeaten streak against Colorado to nine games, including the final seven of last season. After Darin Ruf and Mauricio Dubón continued to thaw their cold bats with big games …