[seahorse] gkr: fix segfault when changing default keyring pass.

[Niels De Graef <nielsdg src gnome org>]

commit a269ed64fc29bb4481e54cd2cca900a0b5481535
Author: Niels De Graef <Niels DeGraef barco com>
Date:   Sat Aug 18 21:53:07 2018 +0200

    gkr: fix segfault when changing default keyring pass.
    
    Fixes #182.

 gkr/gkr-keyring.vala | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)
---
diff --git a/gkr/gkr-keyring.vala b/gkr/gkr-keyring.vala
index 2ec1f761..00995bd6 100644
--- a/gkr/gkr-keyring.vala
+++ b/gkr/gkr-keyring.vala
@@ -189,9 +189,10 @@ public class Keyring : Secret.Collection, Gcr.Collection, Place, Deletable, Lock
                                                    GLib.DBusCallFlags.NONE, -1, null, (obj, res) => {
                        try {
                                var retval = service.get_connection().call.end(res);
+                               warning("RETVAL=%s", (retval==null).to_string());
                                string prompt_path;
                                retval.get("(o)", out prompt_path);
-                               service.prompt_at_dbus_path.begin(prompt_path, null, null, (obj, res) => {
+                               service.prompt_at_dbus_path.begin(prompt_path.dup(), null, null, (obj, res) 
=> {
                                        try {
                                                service.prompt_at_dbus_path.end(res);
                                        } catch (GLib.Error err) {