MAPREUDUCE-5059. Change average merge time on Job overview page to be the time delta between the end of the shuffle and the start of the reduce. Contributed by Omkar Vinit Joshi.


git-svn-id: https://svn.apache.org/repos/asf/hadoop/common/trunk@1467120 13f79535-47bb-0310-9956-ffa450edef68