$ git clone -n https://src.fedoraproject.org/rpms/rust-rand0.7.git /var/lib/mock/f45-build-44219-811/root/chroot_tmpdir/scmroot/rust-rand0.7
Cloning into '/var/lib/mock/f45-build-44219-811/root/chroot_tmpdir/scmroot/rust-rand0.7'...
$ git fetch origin 3fa8208f94e7c4e461311e2e2a7f19d710a00691:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/rust-rand0.7
 * [new ref]         3fa8208f94e7c4e461311e2e2a7f19d710a00691 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 3fa8208 Rebuilt for https://fedoraproject.org/wiki/Fedora_45_Mass_Rebuild