[gthumb] catalogs: error when removing a library

[Paolo Bacchilega <paobac src gnome org>]

commit 2faea49d7b7dc2de1e3248794f344cf3791321ca
Author: Paolo Bacchilega <paobac src gnome org>
Date:   Sat Apr 20 18:27:17 2019 +0200

    catalogs: error when removing a library

 extensions/catalogs/gth-file-source-catalogs.c | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)
---
diff --git a/extensions/catalogs/gth-file-source-catalogs.c b/extensions/catalogs/gth-file-source-catalogs.c
index 5384ec19..8dcae0b5 100644
--- a/extensions/catalogs/gth-file-source-catalogs.c
+++ b/extensions/catalogs/gth-file-source-catalogs.c
@@ -1323,8 +1323,8 @@ remove_from_catalog_end (GError                *error,
        if (error != NULL)
                _gtk_error_dialog_from_gerror_show (data->parent, _("Could not remove the files from the 
catalog"), error);
 
-       g_object_unref (data->catalog);
-       g_object_unref (data->gio_file);
+       _g_object_unref (data->catalog);
+       _g_object_unref (data->gio_file);
        _g_object_list_unref (data->file_list);
        g_free (data);
 }
@@ -1418,6 +1418,7 @@ gth_catalog_manager_remove_files (GtkWindow   *parent,
        data->file_list = _g_file_list_dup (file_list);
        data->gio_file = gth_main_get_gio_file (location->file);
        data->notify = notify;
+       data->catalog = NULL;
 
        _g_file_load_async (data->gio_file,
                            G_PRIORITY_DEFAULT,