[gthumb] fixed a compiler warning

[Paolo Bacchilega <paobac src gnome org>]

commit d9f7dbe2edfa40d7e316d04674a34e1c8697fb03
Author: Paolo Bacchilega <paobac src gnome org>
Date:   Fri Feb 6 10:50:05 2015 +0100

    fixed a compiler warning

 gthumb/gth-image.c |    3 +++
 1 files changed, 3 insertions(+), 0 deletions(-)
---
diff --git a/gthumb/gth-image.c b/gthumb/gth-image.c
index 4b5fffb..94d2fe0 100644
--- a/gthumb/gth-image.c
+++ b/gthumb/gth-image.c
@@ -361,6 +361,9 @@ gth_image_get_original_size (GthImage *image,
                        value_set = TRUE;
                }
                break;
+
+       default:
+               break;
        }
 
        return value_set;