add -i (built-in): use the same indentation as the Perl version

When copying the spaces used to indent non-flat lists in `git add -i`,
one space was appended by mistake. This makes the output of the built-in
version of `git add -i` inconsistent with the Perl version. Let's adjust
the built-in version to produce the same output as the Perl version.

Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

add-interactive.c

@@ -1137,7 +1137,7 @@ int run_add_i(struct repository *r, const struct pathspec *ps)
 	print_file_item_data.color = data.color;
 	print_file_item_data.reset = data.reset;
 
-	strbuf_addstr(&header, "      ");
+	strbuf_addstr(&header, "     ");
 	strbuf_addf(&header, print_file_item_data.modified_fmt,
 		    _("staged"), _("unstaged"), _("path"));
 	opts.list_opts.header = header.buf;