There was a time when emerging markets put the froth into Diageo numbers. Not so much any more. Over the past year, the maker of Guinness - and Johnnie Walker Scotch whisky, Smirnoff vodka and many others - has been wrestling with a host of issues in those markets. Now it's posted weaker-than-expected earnings, hurt by a slowdown in China and volatility elsewhere, with net sales down nine percent.