Import xz-5.0.4.

Import xz-5.0.4.

    * liblzma:

        - Fix lzma_index_init(). It could crash if memory allocation
          failed.

        - Fix the possibility of an incorrect LZMA_BUF_ERROR when a BCJ
          filter is used and the application only provides exactly as
          much output space as is the uncompressed size of the file.

    * Fix "xz -lvv foo.xz". It could crash on some corrupted files.

    * Fix output of "xz --robot -lv" and "xz --robot -lvv" which
      incorrectly printed the filename also in the "foo (x/x)" format.

    * Fix exit status of "xzdiff foo.xz bar.xz".

    * Fix exit status of "xzgrep foo binary_file".