Detail view shows the Lamborghini Aventador Roadster front during the Frankfurt Motor Show (IAA) in Frankfurt, Germany September 13, 2017. REUTERS/Kai Pfaffenbach/File Photo Register now for FREE unlimited access to Reuters.com Register DETROIT, Aug 2 (Reuters) – Wealthy sports car enthusiasts powered Italian supercar brand Lamborghini to record first-half deliveries and profitability, but Chief Executive…