ping: rebase to xz-5.2.0 release + xz-compat-libs removal

[Pavel Raiskup]

Hello list,

upstream (Lasse Collin), _thanks a lot_ BTW,  was able to cut new xz
(stable) release 5.2.0.  I rather write here to inform you about upcoming
rebase in Fedora Rawhide (tomorrow or day after) as there is quite a few
dependant packages..

There shouldn't be a need to rebuild huge amount of packages as the soname
was not bumped and the API upgrade is clean.  There are small nits but the
rebase should be pretty safe (for more info/discussion, look at #1023718
and stop me there possibly).

I also plan to remove old "xz-compat-libs" subpackage in near future,
which, IIRC, is not used at all currently.  Stop this initiative in bug
#1179193 if you feel it is not OK.

Pavel