RFC patchgit-grep: correct exit code with --quiet and -L

> The handling of `status_only` no longer interferes with the handling of
> `unmatch_name_only`.  `--quiet` no longer affects the exit code when using
> `-L`/`--files-without-match`.
>
> Signed-off-by: Anthony Sottile <asottile@umich.edu>
> ---

>  grep.c          | 2 +-
>  t/t7810-grep.sh | 5 +++++
>  2 files changed, 6 insertions(+), 1 deletion(-)
>
> diff --git a/grep.c b/grep.c
> index 2efec0e..c9e7cc7 100644
> --- a/grep.c
> +++ b/grep.c
> @@ -1821,7 +1821,7 @@ static int grep_source_1(struct grep_opt *opt, struct grep_source *gs, int colle
>  		return 0;
>  
>  	if (opt->status_only)
> -		return 0;
> +		return opt->unmatch_name_only;
>  	if (opt->unmatch_name_only) {
>  		/* We did not see any hit, so we want to show this */
>  		show_name(opt, gs->name);
> diff --git a/t/t7810-grep.sh b/t/t7810-grep.sh
> index f106387..2a6679c 100755
> --- a/t/t7810-grep.sh
> +++ b/t/t7810-grep.sh
> @@ -374,6 +374,11 @@ test_expect_success 'grep -L -C' '
>  	test_cmp expected actual
>  '
>  
> +test_expect_success 'grep --files-without-match --quiet' '
> +	git grep --files-without-match --quiet nonexistent_string >actual &&
> +	test_cmp /dev/null actual
> +'
> +
>  cat >expected <<EOF
>  file:foo mmap bar_mmap
>  EOF