[gnome-control-center] common: Fix missing reference

[Georges Basile Stavracas Neto <gbsneto src gnome org>]

commit 65c43b4fac8bd1e65965389c603702518de3efc6
Author: Robert Ancell <robert ancell canonical com>
Date:   Fri Jun 29 16:20:41 2018 +1200

    common: Fix missing reference
    
    Was introduced in 86d1d30

 panels/common/cc-language-chooser.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)
---
diff --git a/panels/common/cc-language-chooser.c b/panels/common/cc-language-chooser.c
index afdd7c548..083549461 100644
--- a/panels/common/cc-language-chooser.c
+++ b/panels/common/cc-language-chooser.c
@@ -404,7 +404,7 @@ cc_language_chooser_new (GtkWidget *parent)
         chooser = WID ("language-dialog");
         priv = g_new0 (CcLanguageChooserPrivate, 1);
         g_object_set_data_full (G_OBJECT (chooser), "private", priv, cc_language_chooser_private_free);
-        g_object_set_data_full (G_OBJECT (chooser), "builder", builder, g_object_unref);
+        g_object_set_data_full (G_OBJECT (chooser), "builder", g_object_ref (builder), g_object_unref);
 
         priv->done_button = WID ("ok-button");
         priv->filter_entry = WID ("language-filter-entry");