$ git clone -n https://src.fedoraproject.org/rpms/f22-backgrounds.git /var/lib/mock/f40-build-2436246-60795/root/chroot_tmpdir/scmroot/f22-backgrounds
Cloning into '/var/lib/mock/f40-build-2436246-60795/root/chroot_tmpdir/scmroot/f22-backgrounds'...
$ git fetch origin 259a83dfbe989d48bb476b84ece4144e2e5c1edb:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/f22-backgrounds
 * [new ref]         259a83dfbe989d48bb476b84ece4144e2e5c1edb -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 259a83d Update f22-backgrounds.spec