MARC BROUSSARD This son of Louisiana’s Cajun country prefers humanity to perfection A signed picture of local native Marc Broussard hangs on the wall at Don’s Country Mart grocery store in Carencro, La., but the acclaimed singer and guitarist doesn’t get treated like a celebrity around here. “They don’t really know what I do,” he says with a laugh. “And that’s fine with me. Here in Cajun country, that’s just how you supplement your...