If the admin encounters corruption and does:
$ ostree admin fsck --delete
We want them to be able to recover the objects easily from the
network; with this patch, they do:
$ ln -s dummyvalue /ostree/repo/transaction
$ ostree refs --delete remotename:branchname
$ ostree pull remotename
This patch avoids the need for the refs --delete; we might as well
force scan the commit, and with this patch we still print that it
changed.