$ git clone -n https://src.fedoraproject.org/rpms/libtorrent.git /var/lib/mock/f45-build-17137-496/root/chroot_tmpdir/scmroot/libtorrent
Cloning into '/var/lib/mock/f45-build-17137-496/root/chroot_tmpdir/scmroot/libtorrent'...
$ git fetch origin 8d01aaf7f37a0cd46ab20310750b3d2a2413eb66:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/libtorrent
 * [new ref]         8d01aaf7f37a0cd46ab20310750b3d2a2413eb66 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 8d01aaf Rebuilt for https://fedoraproject.org/wiki/Fedora_45_Mass_Rebuild