HOUSTON — In a difficult search for positives and small victories in what was an otherwise abysmal Mariners road trip, and a sobering reality check following a 7-2 homestand, these two can be mined: The trip has mercifully ended and they didn’t get completely shut out while being swept in a three-game series by the Astros. Facing the very real possibility of making unwanted club history, the Mariners avoided the dubious distinction of being the first team held scoreless for three consecutive games by scoring a whole two runs off Astros starter Justin Verlander in a 7-2 loss at Minute Maid Park…