[gnome-settings-daemon] print-notifications: Fix a minor warning on shutdown

[Benjamin Berg <bberg src gnome org>]

commit 3967b956d2370e1955efb52c0b0c25ea956c6645
Author: Philip Withnall <withnall endlessm com>
Date:   Fri Mar 6 12:47:28 2020 +0000

    print-notifications: Fix a minor warning on shutdown
    
    The source has already been removed due to returning `G_SOURCE_REMOVE`
    from its callback, so when `finalize()` calls `g_source_remove()`, a
    warning is emitted by GLib.
    
    Fix that by clearing the source ID when returning `G_SOURCE_REMOVE`.
    
    Signed-off-by: Philip Withnall <withnall endlessm com>

 plugins/print-notifications/gsd-print-notifications-manager.c | 1 +
 1 file changed, 1 insertion(+)
---
diff --git a/plugins/print-notifications/gsd-print-notifications-manager.c 
b/plugins/print-notifications/gsd-print-notifications-manager.c
index 53aaccff..395fdd7c 100644
--- a/plugins/print-notifications/gsd-print-notifications-manager.c
+++ b/plugins/print-notifications/gsd-print-notifications-manager.c
@@ -1547,6 +1547,7 @@ gsd_print_notifications_manager_start_idle (gpointer data)
 
         gnome_settings_profile_end (NULL);
 
+        manager->start_idle_id = 0;
         return G_SOURCE_REMOVE;
 }