t2017: mark --orphan/logAllRefUpdates=false test as REFFILES
In reftable, there is no notion of a per-ref 'existence' of a reflog. Each
reflog entry has its own key, so it is not possible to distinguish between
{reflog doesn't exist,reflog exists but is empty}. This makes the logic
in log_ref_setup() (file refs/files-backend.c), which depends on the existence
of the reflog file infeasible.
Signed-off-by: Han-Wen Nienhuys <hanwen@google.com> Reviewed-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>