$ git clone -n https://src.fedoraproject.org/rpms/rust-rustls0.21.git /var/lib/mock/f45-build-44607-815/root/chroot_tmpdir/scmroot/rust-rustls0.21
Cloning into '/var/lib/mock/f45-build-44607-815/root/chroot_tmpdir/scmroot/rust-rustls0.21'...
$ git fetch origin f8cd490cd00c515b7832bf0d237b68449f01702f:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/rust-rustls0.21
 * [new ref]         f8cd490cd00c515b7832bf0d237b68449f01702f -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at f8cd490 Rebuilt for https://fedoraproject.org/wiki/Fedora_45_Mass_Rebuild