[gcr] gck: gck_attribute_get_string() should not return a NULL string

[Stefan Walter <stefw src gnome org>]

commit 794ca1502a562b20ace487c23bb15884df5dd3f3
Author: Stef Walter <stefw collabora co uk>
Date:   Thu Nov 3 14:34:46 2011 +0100

    gck: gck_attribute_get_string() should not return a NULL string
    
     * Fix bug where a NULL string would be returned if the attribute
       was found but was invalid.

 gck/gck-attributes.c |    6 +++++-
 1 files changed, 5 insertions(+), 1 deletions(-)
---
diff --git a/gck/gck-attributes.c b/gck/gck-attributes.c
index 6f3b2ec..b94648e 100644
--- a/gck/gck-attributes.c
+++ b/gck/gck-attributes.c
@@ -1306,6 +1306,7 @@ gboolean
 gck_attributes_find_string (GckAttributes *attrs, gulong attr_type, gchar **value)
 {
 	GckAttribute *attr;
+	gchar *string;
 
 	g_return_val_if_fail (value, FALSE);
 	g_return_val_if_fail (!attrs->locked, FALSE);
@@ -1313,7 +1314,10 @@ gck_attributes_find_string (GckAttributes *attrs, gulong attr_type, gchar **valu
 	attr = gck_attributes_find (attrs, attr_type);
 	if (!attr || gck_attribute_is_invalid (attr))
 		return FALSE;
-	*value = gck_attribute_get_string (attr);
+	string = gck_attribute_get_string (attr);
+	if (string == NULL)
+		return FALSE;
+	*value = string;
 	return TRUE;
 }