Change a test added in
51054177b3 ("index-pack: detect local
corruption in collision check", 2017-04-01) so that the repository
isn't left dirty at the end.
Due to the caveats explained in
720dae5a19 ("config doc: elaborate on
fetch.fsckObjects security", 2018-07-27) even a "fetch" that fails
will write to the local object store, so let's copy the bit-error test
directory before running this test.
Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>