HDFS-4581. DataNode.checkDiskError should not be called on network errors. Contributed by Rohit Kochar.

git-svn-id: https://svn.apache.org/repos/asf/hadoop/common/trunk@1461597 13f79535-47bb-0310-9956-ffa450edef68
YARN-496. Fair scheduler configs are refreshed inconsistently in reinitialize. Contributed by Sandy Ryza

git-svn-id: https://svn.apache.org/repos/asf/hadoop/common/trunk@1461614 13f79535-47bb-0310-9956-ffa450edef68
Merge remote branch 'origin/trunk' into trunk-gd
Merge remote branch 'origin/trunk-gd' into fb-HADOOP-9016-trunk-gd