git: check saves error on disambiguation
This will be useful for disambiguating short OIDs in older
emails when abbreviations were shorter.
Tested against the following script with /path/to/git.git
==> t.perl <==
use strict;
use PublicInbox::Git;
use Data::Dumper;
my $dir = shift or die "Usage: $0 GIT_DIR # (of git.git)";
my $git = PublicInbox::Git->new($dir);
my @res = $git->check('dead');
print Dumper({res => \@res, err=> $git->last_check_err});
@res = $git->check('
5335669531d83d7d6c905bcfca9b5f8e182dc4d4');
print Dumper({res => \@res, err=> $git->last_check_err});