[totem/wip/hadess/brasero-warnings] brasero-disc-recorder: Fix warning on exit

[Bastien Nocera <hadess src gnome org>]

commit db6f7a37538ffd2e0ab500662414e57be2ab1d5e
Author: Bastien Nocera <hadess hadess net>
Date:   Fri Feb 15 00:03:54 2019 +0100

    brasero-disc-recorder: Fix warning on exit
    
    The exact same bug as the one in save-file also afflicted the
    brasero-disc-recorder plugin. We applied the same fix.

 src/plugins/brasero-disc-recorder/totem-disc-recorder.c | 4 ++++
 1 file changed, 4 insertions(+)
---
diff --git a/src/plugins/brasero-disc-recorder/totem-disc-recorder.c 
b/src/plugins/brasero-disc-recorder/totem-disc-recorder.c
index b4a229f07..cab5d5984 100644
--- a/src/plugins/brasero-disc-recorder/totem-disc-recorder.c
+++ b/src/plugins/brasero-disc-recorder/totem-disc-recorder.c
@@ -393,6 +393,10 @@ impl_deactivate (PeasActivatable *plugin)
        TotemDiscRecorderPlugin *pi = TOTEM_DISC_RECORDER_PLUGIN (plugin);
        TotemDiscRecorderPluginPrivate *priv = pi->priv;
 
+       /* impl_activate() exited early */
+       if (priv->totem == NULL)
+               return;
+
        g_signal_handlers_disconnect_by_func (priv->totem, totem_disc_recorder_file_opened, plugin);
        g_signal_handlers_disconnect_by_func (priv->totem, totem_disc_recorder_file_closed, plugin);