Floyd Mayweather is not happy after he was ranked behind Sugar Ray Leonard in a list of all-time great welterweights.    Mayweather retired as an undefeated boxer with 50 wins in all his career fights and won fifteen major world titles, while his American compatriot Sugar Ray Leonard, 64,  who fought 40 times during his time, won 36 of his fights, drew 1 and lost three times. He won world titles in five weight divisions.   Reacting to the recent ranking, …