Commit a56de468 "CI: Avoid using a no-op download location that gives
a 403 error" changed this, but now the direct URL to the file *also*
gives a 403 error. According to the comments in this file, the only
reason we're fetching these URLs is in an effort to pre-seed the
cache of intermediate certificates, so the specific URL that we're
requesting is uninteresting: we just need to fetch *something*.
dbus#546
Signed-off-by: Simon McVittie <smcv@collabora.com>