By Liana B. Baker RIO DE JANEIRO, Aug 13 (Reuters) - Britain's Justin Rose, the player who hit the first Olympic hole in one in 112 years this week, edged ahead in the Olympic men's golf tournament on Saturday after a blistering start. Rose, the world No. 12, fired eagles on the third and fifth holes to take a one-stroke lead over Australian Marcus Fraser who had been sitting atop the leaderboard since Thursday. Sweden's Henrik Stenson, the British Open champion, was also threatening the lead at two strokes back, tied for third place with France's Gregory Bourdy. More...