$ git clone -n https://src.fedoraproject.org/rpms/golang-github-opentracing.git /var/lib/mock/f41-build-1036217-18712/root/chroot_tmpdir/scmroot/golang-github-opentracing
Cloning into '/var/lib/mock/f41-build-1036217-18712/root/chroot_tmpdir/scmroot/golang-github-opentracing'...
$ git fetch origin 0332cf5c3764a09057b6fc3334cfa7bfcb2b2fb8:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/golang-github-opentracing
 * [new ref]         0332cf5c3764a09057b6fc3334cfa7bfcb2b2fb8 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 0332cf5 Fix FTBFS