MAPREDUCE-5102. fix coverage org.apache.hadoop.mapreduce.lib.db and org.apache.hadoop.mapred.lib.db. Contributed by Aleksey Gorshkov, Andrey Klochkov, and Nathan Roberts


git-svn-id: https://svn.apache.org/repos/asf/hadoop/common/trunk@1530816 13f79535-47bb-0310-9956-ffa450edef68