HDFS-5766. In DFSInputStream, do not add datanode to deadNodes after InvalidEncryptionKeyException in fetchBlockByteRange (Liang Xie via Colin Patrick McCabe)

git-svn-id: https://svn.apache.org/repos/asf/hadoop/common/branches/branch-2@1558535 13f79535-47bb-0310-9956-ffa450edef68