drop archive.zfsonlinux.org prefs, no sources anyway

preferences.d/prefer-zfs-on-linux.pref

@@ -1,31 +0,0 @@
-# prefer packages from zfsonlinux.org if they match /zfs|spl/
-
-# Debian 10
-Package: /zfs|spl/
-Pin: release o=archive.zfsonlinux.org,n=buster*
-Pin-Priority: 991
-
-# Debian 11
-Package: /zfs|spl/
-Pin: release o=archive.zfsonlinux.org,n=bullseye*
-Pin-Priority: 891
-
-# Debian 12
-Package: /zfs|spl/
-Pin: release o=archive.zfsonlinux.org,n=bookworm*
-Pin-Priority: 791
-
-# Debian 13
-Package: /zfs|spl/
-Pin: release o=archive.zfsonlinux.org,n=trixie*
-Pin-Priority: 691
-
-# Debian unstable
-Package: /zfs|spl/
-Pin: release o=archive.zfsonlinux.org,n=sid*
-Pin-Priority: 301
-
-# Debian others (experimental, ...)
-Package: /zfs|spl/
-Pin: release o=archive.zfsonlinux.org
-Pin-Priority: -1