Country is no stranger to the influence of traditional Cajun music, but all too often that influence is reduced to an easy cliché—just add accordion for authenticity. The Red Stick Ramblers offer a spirited reminder that the music of their native Baton Rouge, La., and its environs has a lot more to offer than convenient coloration. My Suitcase Is Always Packed is shot through with an energy that’s thoroughly modern, even as its sound remains deeply rooted in history.