(Adds dropped word in first para) By Martyn Herman RIO DE JANEIRO, Aug 3 (Reuters) - Bradley Wiggins says only a gold medal will justify his return to his track cycling roots at the Rio Olympics, declaring the men's team pursuit title is Britain's to lose. The 36-year-old will become his country's most decorated Olympian ahead of fellow cyclist Chris Hoy with a medal of any colour in the team pursuit in Rio's velodrome which would take his career haul to eight. More...