$ git clone -n https://src.fedoraproject.org/rpms/lightdm.git /var/lib/mock/f42-build-side-1-3585732-46907/root/chroot_tmpdir/scmroot/lightdm
Cloning into '/var/lib/mock/f42-build-side-1-3585732-46907/root/chroot_tmpdir/scmroot/lightdm'...
$ git fetch origin c821893e02b559ce5955c472ac2b4369f394ed63:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/lightdm
 * [new ref]         c821893e02b559ce5955c472ac2b4369f394ed63 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at c821893 Convert to %autorelease and %autochangelog