debian/control: Vcs-Git: https://repo.or.cz/r/xz/debian

Alioth (git.debian.org) has been shut down.  Point to a copy of the
packaging repository on repo.or.cz that should be more stable over
time.

Another advantage is that this URL uses https, so it has better
privacy and integrity properties.

Fixes: https://bugs.debian.org/826382
2 files changed