(cherry picked from commit 43b41f22411439c5e23629197fb2fde45dcf0f0f) (cherry picked from commit 219eb22c1571f76df32967a930049d983cbf5024) Conflicts: hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/namenode/NNUpgradeUtil.java hadoop-hdfs-project/hadoop-hdfs/src/test/java/org/apache/hadoop/hdfs/TestDFSUpgrade.java (cherry picked from commit 03798416bfe27383c52e4d9f632fe9fa168c6e95)