HDFS-7300. The getMaxNodesPerRack() method in
BlockPlacementPolicyDefault is flawed. contributed by Kihwal Lee
(cherry picked from commit 3ae84e1ba8928879b3eda90e79667ba5a45d60f8)
HDFS-7305. NPE seen in wbhdfs FS while running SLive. Contributed by Jing Zhao.

Conflicts:
	hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/web/WebHdfsFileSystem.java
HADOOP-11216. Improve Openssl library finding. (cmccabe via yliu)