$ git clone -n https://src.fedoraproject.org/rpms/golang-github-facebook-time.git /var/lib/mock/f40-build-2000336-44451/root/chroot_tmpdir/scmroot/golang-github-facebook-time
Cloning into '/var/lib/mock/f40-build-2000336-44451/root/chroot_tmpdir/scmroot/golang-github-facebook-time'...
$ git fetch origin 3859602bdc295a81c81880e62a752345fa9db419:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/golang-github-facebook-time
 * [new ref]         3859602bdc295a81c81880e62a752345fa9db419 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 3859602 Rebuild latest