HADOOP-9352. Expose UGI.setLoginUser for tests (daryn)


git-svn-id: https://svn.apache.org/repos/asf/hadoop/common/branches/branch-0.23@1452340 13f79535-47bb-0310-9956-ffa450edef68
HDFS-4128. 2NN gets stuck in inconsistent state if edit log replay fails in the middle (kihwal via daryn)


git-svn-id: https://svn.apache.org/repos/asf/hadoop/common/branches/branch-0.23@1452391 13f79535-47bb-0310-9956-ffa450edef68
Merge remote branch 'origin/branch-0.23' into branch-0.23-gd
HDFS-4532. RPC call queue may fill due to current user lookup (daryn)


git-svn-id: https://svn.apache.org/repos/asf/hadoop/common/branches/branch-0.23@1452440 13f79535-47bb-0310-9956-ffa450edef68
svn merge -c 1452475 FIXES: YARN-448. Remove unnecessary hflush from log aggregation (Kihwal Lee via bobby)


git-svn-id: https://svn.apache.org/repos/asf/hadoop/common/branches/branch-0.23@1452478 13f79535-47bb-0310-9956-ffa450edef68
svn merge -c 1452548 FIXES: YARN-345. Many InvalidStateTransitonException errors for ApplicationImpl in Node Manager. Contributed by Robert Parker


git-svn-id: https://svn.apache.org/repos/asf/hadoop/common/branches/branch-0.23@1452555 13f79535-47bb-0310-9956-ffa450edef68
Merge remote branch 'origin/branch-0.23' into branch-0.23-gd
Merge branch 'branch-0.23-gd' of https://github.com/griddynamics/yhadoop-common into fb-HADOOP-9166-branch-0.23-gd

Conflicts:
	hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/security/UserGroupInformation.java
	hadoop-common-project/hadoop-common/src/test/java/org/apache/hadoop/security/TestUserGroupInformation.java