MAPREDUCE-4678. Running the Pentomino example with defaults throws java.lang.NegativeArraySizeException. Contributed by Chris McConnell. (harsh)

git-svn-id: https://svn.apache.org/repos/asf/hadoop/common/branches/branch-0.23@1433413 13f79535-47bb-0310-9956-ffa450edef68