You’ve got to hand it to Dogstar. It’s not easy being taken seriously when the media-and even some fans-don’t really want you to be. But the trio-which includes movie star Keanu Reeves on bass-was well-prepared for its one-hour concert Wednesday night at the Park West. Debuting 15 songs from their upcoming album, “Happy Ending,” the musicians’ aggressive set was a vast improvement over their 1995 Chicago debut at the same venue. Back then, Dogstar appeared tentative and somewhat cowed by the adulation aimed at their famous bassist. This time around, they confidently served up catchy songs with muscular rhythms and strong hooks.