ACCUMULO-1192 applying Kevin Faro's patch to fix du on an empty table

git-svn-id: https://svn.apache.org/repos/asf/accumulo/branches/1.5@1459788 13f79535-47bb-0310-9956-ffa450edef68
ACCUMULO-1192 applying Kevin Faro's patch to fix du on an empty table

git-svn-id: https://svn.apache.org/repos/asf/accumulo/trunk@1459789 13f79535-47bb-0310-9956-ffa450edef68