feature xz-static has correctness issues within compression library

[wcampbell0x2a]

$ cargo build --release --bin unsquashfs --features xz-static
   Compiling backhand v0.9.1 (/home/wcampbell/projects/wcampbell/backhand)
    Finished release [optimized] target(s) in 2.73s

$ ./target/release/unsquashfs -f -d out-rust test-assets/test_openwrt_netgear_ex6100v2/bytes.squashfs
thread 'main' panicked at 'called `Result::unwrap()` on an `Err` value: Custom { kind: InvalidInput, error: Options }', src/bin/unsquashfs.rs:132:48
note: run with `RUST_BACKTRACE=1` environment variable to display a backtrace

squashfs-tools/unsquashfs is just fine

$ unsquashfs test-assets/test_openwrt_netgear_ex6100v2/bytes.squashfs
Parallel unsquashfs: Using 8 processors
1249 inodes (1049 blocks) to write


create_inode: could not create character device squashfs-root/dev/console, because you're not superuser!
[================================================================================================================================================================================================================================================================================================================================================| ] 2297/2298  99%

created 1043 files
created 122 directories
created 205 symlinks
created 0 devices
created 0 fifos
created 0 sockets
created 0 hardlinks

[wcampbell0x2a]

Also linked: alexcrichton/xz2-rs#105