[recipes] image-viewer: fix assertion trying to free a NULL array

[Matthias Clasen <matthiasc src gnome org>]

commit d6e1366fce96a3be759692e5b33cf1a234eb534b
Author: Ignacio Casal Quinteiro <icq gnome org>
Date:   Sun Dec 18 11:19:49 2016 +0100

    image-viewer: fix assertion trying to free a NULL array
    
    https://bugzilla.gnome.org/show_bug.cgi?id=776234

 src/gr-image-viewer.c |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)
---
diff --git a/src/gr-image-viewer.c b/src/gr-image-viewer.c
index ad32567..576f8e9 100644
--- a/src/gr-image-viewer.c
+++ b/src/gr-image-viewer.c
@@ -79,7 +79,7 @@ gr_image_viewer_finalize (GObject *object)
 {
         GrImageViewer *viewer = GR_IMAGE_VIEWER (object);
 
-        g_array_unref (viewer->images);
+        g_clear_pointer (&viewer->images, g_array_unref);
         remove_hide_timeout (viewer);
         g_clear_object (&viewer->gesture);