HADOOP-8712. Change default hadoop.security.group.mapping to JniBasedUnixGroupsNetgroupMappingWithFallback. Contributed by Robert Parker.

git-svn-id: https://svn.apache.org/repos/asf/hadoop/common/trunk@1433624 13f79535-47bb-0310-9956-ffa450edef68
HADOOP-9217. Print thread dumps when hadoop-common tests fail. Contributed by Andrey Klochkov.

git-svn-id: https://svn.apache.org/repos/asf/hadoop/common/trunk@1433713 13f79535-47bb-0310-9956-ffa450edef68
HADOOP-9106. Allow configuration of IPC connect timeout. Contributed by Rober Parker.

git-svn-id: https://svn.apache.org/repos/asf/hadoop/common/trunk@1433747 13f79535-47bb-0310-9956-ffa450edef68
MAPREDUCE-4924. flakey test: org.apache.hadoop.mapred.TestClusterMRNotification.testMR. (rkanter via tucu)

git-svn-id: https://svn.apache.org/repos/asf/hadoop/common/trunk@1433753 13f79535-47bb-0310-9956-ffa450edef68
HDFS-4288. NN accepts incremental BR as IBR in safemode. Contributed by Daryn Sharp.

git-svn-id: https://svn.apache.org/repos/asf/hadoop/common/trunk@1433755 13f79535-47bb-0310-9956-ffa450edef68
Merge branch 'trunk' of github.com:griddynamics/yhadoop-common into trunk-gd
Merge branch 'trunk-gd' of github.com:griddynamics/yhadoop-common into fb-HDFS-4312-trunk-gd