[gnome-photos] main-toolbar: Don't update the title when there is no active item

[Debarshi Ray <debarshir src gnome org>]

commit 9c4dbeab160ea08c9de3bab9a4a45243f8ee9d95
Author: Debarshi Ray <debarshir gnome org>
Date:   Sat Aug 3 13:08:36 2013 +0200

    main-toolbar: Don't update the title when there is no active item
    
    This happens when you are returning from the preview to the overview.
    
    Fixes: https://bugzilla.gnome.org/696794

 src/photos-main-toolbar.c |    3 +++
 1 files changed, 3 insertions(+), 0 deletions(-)
---
diff --git a/src/photos-main-toolbar.c b/src/photos-main-toolbar.c
index 35e24ea..15f722a 100644
--- a/src/photos-main-toolbar.c
+++ b/src/photos-main-toolbar.c
@@ -204,6 +204,9 @@ photos_main_toolbar_item_active_changed (PhotosBaseManager *manager, GObject *ob
   PhotosMainToolbarPrivate *priv = self->priv;
   PhotosWindowMode window_mode;
 
+  if (object == NULL)
+    return;
+
   window_mode = photos_mode_controller_get_window_mode (priv->mode_cntrlr);
   if (window_mode == PHOTOS_WINDOW_MODE_PREVIEW)
     photos_main_toolbar_set_toolbar_title (self);