This is a follow-on to I39cb9dc0aa52cf5b20545baf4acacc21c5459f2a; as
buster has no backports we need to skip this in the reprepro
configuration. It's a bit hacky, but we can revert when it is
available.
Change-Id: I60e231f23999d0af9c899a30822c71702befb2bd