Everything is relative. At a Lollapalooza or a rock festival, Red Hot Chili Peppers are funky. At Jazz Fest, they’re a rock band. They love funk, and Flea can be a funky bassist, but their rock is stronger than their funk, and it shows in a place where funkier bands are all around. Sunday, they surprised almost no one when they brought out The Meters with Ivan Neville subbing for Art to join them on the set-ending “Give It Away.” The two bands jammed together at Voodoo in 2006, and Meters’ guitarist Leo Nocentelli played the Acura Stage a few hours before the Chili Peppers.