OPT__ABBREV() has the same behavior as the deleted code with one
difference: it does check for valid number and error out if not. And the
'40' change is self explanatory.
Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>