[brasero] Fix a crash when there is no error

[Philippe Rouquier <philippr src gnome org>]

commit 20470676de591a59e75ec741de453c9e1417e6c0
Author: Philippe Rouquier <bonfire-app wanadoo fr>
Date:   Wed May 27 20:06:57 2009 +0200

    Fix a crash when there is no error
---
 libbrasero-burn/brasero-src-image.c |    3 +++
 1 files changed, 3 insertions(+), 0 deletions(-)

diff --git a/libbrasero-burn/brasero-src-image.c b/libbrasero-burn/brasero-src-image.c
index bd49515..b4f93e6 100644
--- a/libbrasero-burn/brasero-src-image.c
+++ b/libbrasero-burn/brasero-src-image.c
@@ -238,6 +238,9 @@ brasero_src_image_update (BraseroSrcImage *self)
 		goto end;
 	}
 	else if (result != BRASERO_BURN_OK) {
+		if (!error)
+			goto end;
+
 		/* Translators: %s is a path and image refers to a disc image */
 		string = g_strdup_printf (_("\"%s\": unknown image type"), path);
 		gtk_widget_set_tooltip_text (GTK_WIDGET (self), error->message);