Even though Chevrolet’s new Camaro convertible won’t be making its in-the-metal debut until next month’s L.A. Auto Show, John Hennessey and crew are already preparing to make the General’s newest droptop even fiestier. In the process, they’re also giving people who weren’t able to pick up one of their limited edition carnivorous Camaros this year a second chance.You see, Hennessey only produced