$ git clone -n https://src.fedoraproject.org/rpms/aardvark-dns.git /var/lib/mock/f40-build-1723469-24647/root/chroot_tmpdir/scmroot/aardvark-dns
Cloning into '/var/lib/mock/f40-build-1723469-24647/root/chroot_tmpdir/scmroot/aardvark-dns'...
$ git fetch origin 44b35cd7531f31f15843d6531dcc5957bbd3746a:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/aardvark-dns
 * [new ref]         44b35cd7531f31f15843d6531dcc5957bbd3746a -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 44b35cd rebuild