SAN FRANCISCO — Casey Schmitt did it again. The day after giving the Giants the lead with a late blast to left field, Schmitt showed off his clutch gene to the Marlins’ bullpen for a second time in as many games . Schmitt launched a three-run shot to left in the seventh inning that broke a tie and gave the Giants their first lead in an eventual 6-3 win to secure the three-game series. The heroics ensured the longest start of Landen Roupp’s career didn’t go to waste. Roupp took the mound to