do not write null sha1s to on-disk index

diff --git a/git-difftool.perl b/git-difftool.perl
index ced1615e216018bc20303cd91eaea05c69cb6b11..09b65f1770c09824df5543d208d1df0e9a60d831 100755 (executable)
--- a/git-difftool.perl
+++ b/git-difftool.perl
@@ -97,7 +97,7 @@ sub generate_command
                        $prompt = 'yes';
                        next;
                }
-               if ($arg eq '-h' || $arg eq '--help') {
+               if ($arg eq '-h') {
                        usage();
                }
                push @command, $arg;