Temporary disable ftp.halifax.rwth-aachen.de, server down for maintenance

Temporary disable ftp.halifax.rwth-aachen.de, server down for maintenance

Quoting from mail (Message-ID: <20201018104147.GE17790@home.c-otto.de>):

| our mirror ftp.halifax.rwth-aachen.de will be down for the next couple
| of days (or weeks). We sadly lost our main file system (BTRFS) and are
| unable to repair it. As such, we will set up a new solution (without
| BTRFS). This also means that we will need to download everything from
| our upstream mirrors, which will take a bit of time for around 40 TByte
| of data.
|
| Please disable ftp.halifax.rwth-aachen.de (ftp2.de.debian.org,
| de3.mirror.archlinuxarm.org, rwthaachen.dl.osdn.jp, ...) in your
| redirection systems, and redirect DNS records where appropriate.