A paroled killer’s “Obama” bumper sticker was the break that helped cops nab the man accused of the cold-blooded murder of a Tedeschi’s convenience store clerk, jurors in Edward Corliss’ murder trial learned yesterday. “It struck me as odd,” state parole officer Kevin Devlin testified yesterday in Suffolk Superior Court about the campaign sticker plastered on the back of parolee Corliss’ white Plymouth Acclaim. “He’s a guy from Somerville, so I was surprised he was supporting Obama,” Devlin said. “I made a joke about it. He said it was on the car when they bought it.” Corliss is on trial...