$ git clone -n https://src.fedoraproject.org/rpms/rshim.git /var/lib/mock/f45-build-34685-690/root/chroot_tmpdir/scmroot/rshim
Cloning into '/var/lib/mock/f45-build-34685-690/root/chroot_tmpdir/scmroot/rshim'...
$ git fetch origin aac390dcdb03ddef4e38c2cca7c91ae6e99cfbc9:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/rshim
 * [new ref]         aac390dcdb03ddef4e38c2cca7c91ae6e99cfbc9 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at aac390d Update to 2.8.5 upstream release