HADOOP-10780. hadoop_user_info_alloc fails on FreeBSD due to incorrect sysconf use (trtrmitya via cmccabe)

git-svn-id: https://svn.apache.org/repos/asf/hadoop/common/branches/branch-2@1610472 13f79535-47bb-0310-9956-ffa450edef68
HDFS-2856. Merging change r1610474 from trunk to branch-2.

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HADOOP-10810. Merging change r1610524 from trunk to branch-2.

git-svn-id: https://svn.apache.org/repos/asf/hadoop/common/branches/branch-2@1610526 13f79535-47bb-0310-9956-ffa450edef68