YARN-2112. Fixed yarn-common's pom.xml to include jackson dependencies so that both Timeline Server and client can access them. Contributed by Zhijie Shen.
svn merge --ignore-ancestry -c 1598373 ../../trunk/


git-svn-id: https://svn.apache.org/repos/asf/hadoop/common/branches/branch-2@1598374 13f79535-47bb-0310-9956-ffa450edef68