Merge -r 1446182:1446183 from trunk to branch-2. Fixes: HADOOP-9154. SortedMapWritable#putAll() doesn't add key/value classes to the map. Contributed by Karthik Kambatla.

git-svn-id: https://svn.apache.org/repos/asf/hadoop/common/branches/branch-2@1446186 13f79535-47bb-0310-9956-ffa450edef68
Merge remote branch 'origin/branch-2' into branch-2-gd
Merge remote branch 'origin/branch-2-gd' into fb-HADOOP-9078-branch-2-gd