HIVE-7266 : Optimized HashTable with vectorized map-joins results in String columns extending (Sergey Shelukhin, reviewed by Matt McCline and Jitendra Nath Pandey)

git-svn-id: https://svn.apache.org/repos/asf/hive/trunk@1613322 13f79535-47bb-0310-9956-ffa450edef68