$ git clone -n https://github.com/xcp-ng-rpms/samba.git /var/lib/mock/v8.3-u-pcoval1-11128-29545/root/chroot_tmpdir/scmroot/samba
Cloning into '/var/lib/mock/v8.3-u-pcoval1-11128-29545/root/chroot_tmpdir/scmroot/samba'...
$ git fetch origin aab15de757baff32484e328c592680f20c53aa72:KOJI_FETCH_HEAD
From https://github.com/xcp-ng-rpms/samba
 * [new ref]         aab15de757baff32484e328c592680f20c53aa72 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at aab15de bump release for test build