HADOOP-9374. Add tokens from -tokenCacheFile into UGI (daryn)


git-svn-id: https://svn.apache.org/repos/asf/hadoop/common/trunk@1454019 13f79535-47bb-0310-9956-ffa450edef68
HDFS-4546. Use DFSUtil.getSpnegoKeytabKey() to get the spnego keytab key in secondary namenode and namenode http server. Contributed by Arpit Agarwal.

git-svn-id: https://svn.apache.org/repos/asf/hadoop/common/trunk@1454021 13f79535-47bb-0310-9956-ffa450edef68