$ git clone -n https://github.com/xcp-ng-rpms/samba.git /var/lib/mock/v8.3-u-pcoval1-11273-29617/root/chroot_tmpdir/scmroot/samba
Cloning into '/var/lib/mock/v8.3-u-pcoval1-11273-29617/root/chroot_tmpdir/scmroot/samba'...
$ git fetch origin 9aa8e4cc27c39b9f9ac8cabc0b5c8aeedc5b4370:KOJI_FETCH_HEAD
From https://github.com/xcp-ng-rpms/samba
 * [new ref]         9aa8e4cc27c39b9f9ac8cabc0b5c8aeedc5b4370 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 9aa8e4c bump release for test build