HOUSTON (AP) — Héctor Herrera and Griffin Dorsey scored first-half goals and the Houston Dynamo breezed to a 4-1 victory over the Vancouver Whitecaps on Wednesday night. Houston (12-10-7) ran its regular-season unbeaten streak to seven (4-0-3), its longest run since an eight-match streak in 2012. The Dynamo scored first on an unassisted goal by Herrera in the 13th minute. It was his fourth goal of the season. Houston took a 2-0 lead into halftime when Griffin Dorsey took a pass from Corey Baird