The legacy of John Fogerty can’t be overstated when it comes to American roots music. His songs, both solo and with Creedence Clearwater Revival, sum up most of what’s great about music, from blues to Bakersfield, from country to gospel, all recast in a rock context. Yet the singer-songwriter-guitarist had never set foot in the swamps before recording classics like “Born on the Bayou,” and “Bad Moon Rising.” OffBeat