YARN-518. Fair Scheduler's document link could be added to the hadoop 2.x main doc page. (sandyr via tucu)

git-svn-id: https://svn.apache.org/repos/asf/hadoop/common/trunk@1469091 13f79535-47bb-0310-9956-ffa450edef68
YARN-476. ProcfsBasedProcessTree info message confuses users. (sandyr via tucu)

git-svn-id: https://svn.apache.org/repos/asf/hadoop/common/trunk@1469093 13f79535-47bb-0310-9956-ffa450edef68
MAPREDUCE-5128. mapred-default.xml is missing a bunch of history server configs. (sandyr via tucu)

git-svn-id: https://svn.apache.org/repos/asf/hadoop/common/trunk@1469095 13f79535-47bb-0310-9956-ffa450edef68
Merge remote branch 'origin/trunk' into trunk-gd
Merge remote branch 'origin/trunk-gd' into fb-HDFS-4310-trunk-gd