Skeptics scoffed last summer when Mickey Kapoor, owner of the Khyber North Indian Grill [2510 Richmond, (713)942-9424], joined forces with native New Orleanian Troy Roth to create The Gumbo Shop [2207 Richmond, (713)522-1311]. It sounded like an improbable notion, frankly, and featured what some thought an unlucky location: the site…