* Britain's Kenny claims sixth career gold * Dutchman Matthijs Buchli clinches silver * Malaysia's Azizulhasni Awang takes bronze (Adds quote, colour) By Stephen Eisenhammer RIO DE JANEIRO, Aug 16 (Reuters) - Britain's Jason Kenny won the men's track cycling keirin on Tuesday, taking his gold medal haul to six and equalling Chris Hoy's record for the country's most Olympic titles. In a tense race around Rio's boards, Kenny had too much pace down the final stretch, recovering from a slow start to finish just clear. More...