No .xz encoder creates files with empty LZMA2 streams,
but such files would still be valid and decompressors
must accept them.
Note that empty .xz files are a different thing than
empty LZMA2 streams. This bug didn't affect typical .xz
files that had no uncompressed data.
Signed-off-by: Lasse Collin <lasse.collin@tukaani.org>
Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
