[libgfbgraph] photo: fix return value as a guint in case the given object isn't a GFBGraphPhoto

[Álvaro Peña <alvaropg src gnome org>]

commit c7d3286d369bd4e0326b2d065643f86a2966cf93
Author: Álvaro Peña <alvaropg gmail com>
Date:   Mon Aug 26 19:22:27 2013 +0200

    photo: fix return value as a guint in case the given object isn't a GFBGraphPhoto

 gfbgraph/gfbgraph-photo.c |    4 ++--
 1 files changed, 2 insertions(+), 2 deletions(-)
---
diff --git a/gfbgraph/gfbgraph-photo.c b/gfbgraph/gfbgraph-photo.c
index 50bf0f7..1a26836 100644
--- a/gfbgraph/gfbgraph-photo.c
+++ b/gfbgraph/gfbgraph-photo.c
@@ -480,7 +480,7 @@ gfbgraph_photo_get_default_source_uri (GFBGraphPhoto *photo)
 guint
 gfbgraph_photo_get_default_width (GFBGraphPhoto *photo)
 {
-        g_return_val_if_fail (GFBGRAPH_IS_PHOTO (photo), -1);
+        g_return_val_if_fail (GFBGRAPH_IS_PHOTO (photo), 0);
 
         return photo->priv->width;
 }
@@ -494,7 +494,7 @@ gfbgraph_photo_get_default_width (GFBGraphPhoto *photo)
 guint
 gfbgraph_photo_get_default_height (GFBGraphPhoto *photo)
 {
-        g_return_val_if_fail (GFBGRAPH_IS_PHOTO (photo), -1);
+        g_return_val_if_fail (GFBGRAPH_IS_PHOTO (photo), 0);
 
         return photo->priv->height;
 }