$ git clone -n https://src.fedoraproject.org/rpms/golang-github-cloudflare-cfssl.git /var/lib/mock/f40-build-799029-142136/root/chroot_tmpdir/scmroot/golang-github-cloudflare-cfssl
Cloning into '/var/lib/mock/f40-build-799029-142136/root/chroot_tmpdir/scmroot/golang-github-cloudflare-cfssl'...
$ git fetch origin 50e9c0a30c27887b7abe564e27db1fd8a883e902:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/golang-github-cloudflare-cfssl
 * [new ref]         50e9c0a30c27887b7abe564e27db1fd8a883e902 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 50e9c0a Fix FTBFS