There was a time historically where Launchpad buildd might have relied
on that behaviour, but this shouldn't be the case anymore as it sets
priority manually when building backports.
Meanwhile any other builds using buildd images (e.g. snapcraft)
shouldn't default to backports unless required. (lp: #2009871)
Refs:
- [1] https://git.launchpad.net/launchpad-buildd/commit?id=c2ebcb6752
Instead of injecting an empty resolv.conf with an includes.chroot, we'll
inject it in late with a hook. The empty resolv.conf breaks DNS early in
the build, and causes some binary hooks to fail.
We don't want the symlink to /run/systemd/resolve/stub-resolv.conf, and
launchpad-buildd will inject its own version if it doesn't get confused by a
symlink.
