$ git clone -n https://src.fedoraproject.org/rpms/rust-linux-raw-sys.git /var/lib/mock/f40-build-2642236-66450/root/chroot_tmpdir/scmroot/rust-linux-raw-sys
Cloning into '/var/lib/mock/f40-build-2642236-66450/root/chroot_tmpdir/scmroot/rust-linux-raw-sys'...
$ git fetch origin 2c2fb0d3361062748e0f02f4b192096c26a43ce7:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/rust-linux-raw-sys
 * [new ref]         2c2fb0d3361062748e0f02f4b192096c26a43ce7 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 2c2fb0d Update to version 0.6.4; Fixes RHBZ#2258676