If the brake is functioning well but just rubbing at one spot, no need to mess with the brake itself. Rotors are easily bent and need to be incredibly straight to prevent rubbing due to the very tight clearances in the disc brake system. Just use your hand or a wrench to GENTLY bend it back. It doesn't take much. Realize this will happen from time to time, and IMO it's one of the easiest jobs you could do. Easier than changing a flat tube. So you might as well do it yourself.