$ git clone -n https://src.fedoraproject.org/rpms/golang-github-opentracing-contrib-stdlib.git /var/lib/mock/f41-build-1036213-18712/root/chroot_tmpdir/scmroot/golang-github-opentracing-contrib-stdlib
Cloning into '/var/lib/mock/f41-build-1036213-18712/root/chroot_tmpdir/scmroot/golang-github-opentracing-contrib-stdlib'...
$ git fetch origin b49897c2eda8c03e78e74e9eb2d5a1504a10ee17:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/golang-github-opentracing-contrib-stdlib
 * [new ref]         b49897c2eda8c03e78e74e9eb2d5a1504a10ee17 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at b49897c Fix FTBFS