SAN DIEGO — Cam Smith homered twice Friday night and the visiting Houston Astros made it 13 wins in 16 games by doubling up the San Diego Padres 6-3. Smith initiated scoring in the top of the second with his first solo homer, a liner into the left field seats, and then walloped his second homer to lead off the sixth. Ronel Blanco started and worked the first 4 2/3 innings, yielding four hits and three runs with three walks and a strikeout. Robbie Ray (10-7) lost in his first San Diego start, breaking a string of 12 straight starts in which he hadn’t lost. Ray gave up seven hits and four runs in five innings, issuing five walks and fanning two.