$ git clone -n https://src.fedoraproject.org/rpms/rubygem-syck.git /var/lib/mock/f45-build-35378-695/root/chroot_tmpdir/scmroot/rubygem-syck
Cloning into '/var/lib/mock/f45-build-35378-695/root/chroot_tmpdir/scmroot/rubygem-syck'...
$ git fetch origin 8048843d7b1554256cad064ad87200fe17eaafe5:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/rubygem-syck
 * [new ref]         8048843d7b1554256cad064ad87200fe17eaafe5 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 8048843 1.6.2