debian/liblzma: Drop liblzma.so.2 compatibility

liblzma.so.2 was a Debian-specific ABI that has not been in Debian
since Debian 6.0, which reached its end of support in February, 2016.
Simplify by removing support for processes making use of that ABI and
the current upstream ABI at the same time.

Requested-by: Josh Triplett <josh@joshtriplett.org>
9 files changed