checkout-index loads the index before parsing options. Erroring out
is counterproductive at that point if the operator is hunting for a
command to recover useful data from the broken repository.
[jn: new commit message, tests]
Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com>
Signed-off-by: Jonathan Nieder <jrnieder@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
