MAPREDUCE-2722. [Gridmix] Gridmix simulated job's map's hdfsBytesRead counter is wrong when compressed input is used.(ravigummadi via tgraves)

git-svn-id: https://svn.apache.org/repos/asf/hadoop/common/branches/branch-2@1461236 13f79535-47bb-0310-9956-ffa450edef68