$ git clone -n https://src.fedoraproject.org/rpms/golang-github-docker-go.git /var/lib/mock/f40-build-2263433-54533/root/chroot_tmpdir/scmroot/golang-github-docker-go
Cloning into '/var/lib/mock/f40-build-2263433-54533/root/chroot_tmpdir/scmroot/golang-github-docker-go'...
$ git fetch origin c0e7d7f7cd53df6af0b71dcdcc7e07430c6ec6c7:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/golang-github-docker-go
 * [new ref]         c0e7d7f7cd53df6af0b71dcdcc7e07430c6ec6c7 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at c0e7d7f Remove deprecated %patchN syntax