OAKLAND, Calif. — The A’s continued to come up empty at the plate Saturday, wasting a strong performance from starter Frankie Montas and losing, 2-0, to the Texas Rangers at the Coliseum before a crowd of 9,120. The game was scoreless until Brad Miller hit a two-run single in the seventh against Domingo Acevedo, bringing home two runs charged to Montas, who fell to 2-2. The second of those runs came on a catcher’s obstruction call at the plate and led to the ejection of A’s manager Mark Kotsay. Montas got the first out of the eighth on a ground out before giving up singles to Adolis Garcia and…