[gnome-flashback] shell: fix memory leak

[Alberts Muktupāvels <muktupavels src gnome org>]

commit 730dbed2d3a0695a958c93faf0e04bb97d6b5f12
Author: Alberts Muktupāvels <alberts muktupavels gmail com>
Date:   Thu Jul 18 20:17:44 2019 +0300

    shell: fix memory leak
    
    https://bugs.launchpad.net/ubuntu/+source/gnome-flashback/+bug/1760336

 gnome-flashback/libshell/flashback-shell.c | 8 ++++++++
 1 file changed, 8 insertions(+)
---
diff --git a/gnome-flashback/libshell/flashback-shell.c b/gnome-flashback/libshell/flashback-shell.c
index 4ab2a43..0901903 100644
--- a/gnome-flashback/libshell/flashback-shell.c
+++ b/gnome-flashback/libshell/flashback-shell.c
@@ -488,6 +488,14 @@ flashback_shell_finalize (GObject *object)
       shell->bus_name = 0;
     }
 
+  if (shell->iface != NULL)
+    {
+      g_dbus_interface_skeleton_unexport (shell->iface);
+
+      g_object_unref (shell->iface);
+      shell->iface = NULL;
+    }
+
   if (shell->grabbed_accelerators)
     {
       g_hash_table_destroy (shell->grabbed_accelerators);