HADOOP-10207. TestUserGroupInformation#testLogin is flaky (jxiang via cmccabe)

git-svn-id: https://svn.apache.org/repos/asf/hadoop/common/trunk@1556664 13f79535-47bb-0310-9956-ffa450edef68
HADOOP-10214. Fix multithreaded correctness warnings in ActiveStandbyElector (Liang Xie via kasha)

git-svn-id: https://svn.apache.org/repos/asf/hadoop/common/trunk@1556734 13f79535-47bb-0310-9956-ffa450edef68
HDFS-5721. sharedEditsImage in Namenode#initializeSharedEdits() should be closed before method returns. (Ted Yu via junping_du)

git-svn-id: https://svn.apache.org/repos/asf/hadoop/common/trunk@1556803 13f79535-47bb-0310-9956-ffa450edef68
Merge remote-tracking branch: upstream/trunk