$ git clone -n https://src.fedoraproject.org/rpms/golang-gopkg-rethinkdb-6.git /var/lib/mock/f41-build-1036607-18741/root/chroot_tmpdir/scmroot/golang-gopkg-rethinkdb-6
Cloning into '/var/lib/mock/f41-build-1036607-18741/root/chroot_tmpdir/scmroot/golang-gopkg-rethinkdb-6'...
$ git fetch origin 1cefa35c1f9a4f147ccac32483e0e4cc06cc88d9:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/golang-gopkg-rethinkdb-6
 * [new ref]         1cefa35c1f9a4f147ccac32483e0e4cc06cc88d9 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 1cefa35 Fix FTBFS