YARN-479. NM retry behavior for connection to RM should be similar for lost heartbeats (Jian He via bikas)

git-svn-id: https://svn.apache.org/repos/asf/hadoop/common/trunk@1465731 13f79535-47bb-0310-9956-ffa450edef68
HDFS-3981. Fix handling of FSN lock in getBlockLocations. Contributed by Xiaobo Peng and Todd Lipcon.

git-svn-id: https://svn.apache.org/repos/asf/hadoop/common/trunk@1465751 13f79535-47bb-0310-9956-ffa450edef68
Merge remote branch 'origin/trunk' into trunk-gd
Merge remote branch 'origin/trunk-gd' into fb-HDFS-4311-trunk-gd