$ git clone -n https://src.fedoraproject.org/rpms/golang-gopkg-mgo-2.git /var/lib/mock/f38-build-side-42-init-devel-608243-26258/root/chroot_tmpdir/scmroot/golang-gopkg-mgo-2
Cloning into '/var/lib/mock/f38-build-side-42-init-devel-608243-26258/root/chroot_tmpdir/scmroot/golang-gopkg-mgo-2'...
$ git fetch origin b897baa66f8dcbd68ea25fb50bde6e131267acfa:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/golang-gopkg-mgo-2
 * [new ref]         b897baa66f8dcbd68ea25fb50bde6e131267acfa -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at b897baa %gometa -f