MAPREDUCE-3829. [Gridmix] Gridmix should give better error message when input data directory already exists and -generate opton is erate opton is
+    given.(ravi

git-svn-id: https://svn.apache.org/repos/asf/hadoop/common/branches/branch-2@1461233 13f79535-47bb-0310-9956-ffa450edef68