HDFS-4577. Webhdfs operations should declare if authentication is required. Contributed by Daryn Sharp.

git-svn-id: https://svn.apache.org/repos/asf/hadoop/common/branches/branch-0.23@1454523 13f79535-47bb-0310-9956-ffa450edef68
svn merge -c 1205697 Merging from trunk to branch-0.23 to fix HADOOP-7358.

git-svn-id: https://svn.apache.org/repos/asf/hadoop/common/branches/branch-0.23@1454530 13f79535-47bb-0310-9956-ffa450edef68
svn merge -c 1375790 Merging from trunk to branch-0.23 to fix HADOOP-8711.

git-svn-id: https://svn.apache.org/repos/asf/hadoop/common/branches/branch-0.23@1454534 13f79535-47bb-0310-9956-ffa450edef68
svn merge -c 1376054 Merging from truk to branch-0.23 to fix HDFS-3817.

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Merge remote branch 'origin/branch-0.23' into branch-0.23-gd