git-commit: color status output when color.ui is set

When using "git commit" and there was nothing to commit (the editor
wasn't launched), the status output wasn't colored, even though color.ui
was set. Only when setting color.status it worked.

Signed-off-by: Markus Heidelberg <markus.heidelberg@web.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

builtin-commit.c

@@ -945,6 +945,9 @@ int cmd_commit(int argc, const char **argv, const char *prefix)
 
 	git_config(git_commit_config, NULL);
 
+	if (wt_status_use_color == -1)
+		wt_status_use_color = git_use_color_default;
+
 	argc = parse_and_validate_options(argc, argv, builtin_commit_usage, prefix);
 
 	index_file = prepare_index(argc, argv, prefix);