xz: Update to version 5.4.6

xz: Update to version 5.4.6

- Update from version 5.4.5 to 5.4.6
- Update of rootfile
- Changelog
    5.4.6
	    * Fixed a bug involving internal function pointers in liblzma not
	      being initialized to NULL. The bug can only be triggered if
	      lzma_filters_update() is called on a LZMA1 encoder, so it does
	      not affect xz or any application known to us that uses liblzma.
	    * xz:
	        - Fixed a regression introduced in 5.4.2 that caused encoding
	          in the raw format to unnecessarily fail if --suffix was not
	          used. For instance, the following command no longer reports
	          that --suffix must be used:
	              echo foo | xz --format=raw --lzma2 | wc -c
	        - Fixed an issue on MinGW-w64 builds that prevented reading
	          from or writing to non-terminal character devices like NUL.
	    * Added a new test.

Signed-off-by: Adolf Belka <adolf.belka@ipfire.org>
Signed-off-by: Michael Tremer <michael.tremer@ipfire.org>