HDFS-7077. Separate CipherSuite from crypto protocol version. (wang)

(cherry picked from commit e96ce6f3e3e549202ce3c48d4733ba34098870ad)

Conflicts:
	hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/protocolPB/PBHelper.java
	hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/namenode/FSNamesystem.java