MAPREDUCE-5481. Enable uber jobs to have multiple reducers (Sandy Ryza)

git-svn-id: https://svn.apache.org/repos/asf/hadoop/common/branches/branch-2@1541846 13f79535-47bb-0310-9956-ffa450edef68
HADOOP-10067 Missing POM dependency on jsr305

git-svn-id: https://svn.apache.org/repos/asf/hadoop/common/branches/branch-2@1541861 13f79535-47bb-0310-9956-ffa450edef68
Merge remote branch 'origin/branch-2' into branch-2-gd
Merge remote branch 'origin/branch-2-gd' into fb-MAPREDUCE-4884-branch-2-gd