Merge remote-tracking branch 'apache/trunk' into HDFS-7285

Conflicts:
	hadoop-hdfs-project/hadoop-hdfs-client/src/main/java/org/apache/hadoop/hdfs/DFSOutputStream.java
	hadoop-hdfs-project/hadoop-hdfs-client/src/main/java/org/apache/hadoop/hdfs/DataStreamer.java

Change-Id: I53ec1c426dc988d6c4a2c87b00caef49c4057010