kobject: fix kset sample error path

Previously, example_init() leaked a kset if any of the object creations
failed.  This fixes the leak by calling kset_unregister() in the error
path.
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

samples/kobject/kset-example.c

@@ -262,6 +262,7 @@ static int __init example_init(void)
 bar_error:
 	destroy_foo_obj(foo_obj);
 foo_error:
+	kset_unregister(example_kset);
 	return -EINVAL;
 }