Jim Harbaugh says A.J. Jenkins “did OK” despite zero catches

San Francisco receiver A.J. Jenkins did not catch a pass in the 49ers’ second preseason game, meaning he still has just one catch in the preseason — the one he promptly fumbled. But 49ers coach Jim Harbaugh is defending Jenkins’s performance. “He did OK,” Harbaugh said of Smith. “It’s a step.” Jenkins did have a…