Merge -c 1497922 from trunk to branch-2 to fix HADOOP-9665. Fixed BlockDecompressorStream#decompress to return -1 rather than throw EOF at end of file. Contributed by Zhijie Shen.

git-svn-id: https://svn.apache.org/repos/asf/hadoop/common/branches/branch-2@1497923 13f79535-47bb-0310-9956-ffa450edef68