PIG-3675: Documentation for AccumuloStorage

git-svn-id: https://svn.apache.org/repos/asf/pig/trunk@1570332 13f79535-47bb-0310-9956-ffa450edef68
PIG-3675: Documentation for AccumuloStorage

git-svn-id: https://svn.apache.org/repos/asf/pig/trunk@1570333 13f79535-47bb-0310-9956-ffa450edef68