All spring, Yovani Gallardo spoke with urgency about bouncing back from a subpar 2013 season. Now he’s backing up the big talk with big pitching. Gallardo — who hasn’t allowed a run in 12 2/3 innings this season — led the Brewers to a 4-0 win and their first three-game sweep of the Red Sox in more than two decades by scattering seven hits over 6 2/3 scoreless innings on Sunday at Fenway Park.