[vala/0.40] gio-2.0: Result of DBusMessage.get_header() is unowned

[Rico Tzschichholz <ricotz src gnome org>]

commit 3d6143074a8bd955d1760c2b95fbbf9735810b0e
Author: Rico Tzschichholz <ricotz ubuntu com>
Date:   Wed Nov 7 12:15:25 2018 +0100

    gio-2.0: Result of DBusMessage.get_header() is unowned

 vapi/gio-2.0.vapi | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)
---
diff --git a/vapi/gio-2.0.vapi b/vapi/gio-2.0.vapi
index 19e19e097..77bff391f 100644
--- a/vapi/gio-2.0.vapi
+++ b/vapi/gio-2.0.vapi
@@ -778,7 +778,7 @@ namespace GLib {
                public unowned string get_destination ();
                public unowned string get_error_name ();
                public GLib.DBusMessageFlags get_flags ();
-               public GLib.Variant get_header (GLib.DBusMessageHeaderField header_field);
+               public unowned GLib.Variant? get_header (GLib.DBusMessageHeaderField header_field);
                [CCode (array_length = false, array_null_terminated = true)]
                public uchar[] get_header_fields ();
                public unowned string get_interface ();