[gnome-photos] base-item: Avoid pointing to invalid memory

[Debarshi Ray <debarshir src gnome org>]

commit 215026f4d199dbf782668d8b7cc5799f5310c6a3
Author: Debarshi Ray <debarshir gnome org>
Date:   Fri Jul 8 10:24:22 2016 +0200

    base-item: Avoid pointing to invalid memory
    
    When setting a new default GAppInfo we should not only free the old
    name, but also NULLify it. Otherwise, if were passed a NULL GAppInfo,
    then the pointers to the name and the object would be out of sync. One
    would be non-NULL and the other NULL. We would also confuse the NULL
    checks and risk accessing invalid memory.

 src/photos-base-item.c |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)
---
diff --git a/src/photos-base-item.c b/src/photos-base-item.c
index 5f94198..4c76b23 100644
--- a/src/photos-base-item.c
+++ b/src/photos-base-item.c
@@ -2750,7 +2750,7 @@ photos_base_item_set_default_app (PhotosBaseItem *self, GAppInfo *default_app)
     return;
 
   g_clear_object (&priv->default_app);
-  g_free (priv->default_app_name);
+  g_clear_pointer (&priv->default_app_name, g_free);
 
   if (default_app == NULL)
     return;