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 <[e-mail]>
Signed-off-by: Greg Kroah-Hartman <[e-mail]>

samples/kobject/kset-example.c

···
 bar_error:
 	destroy_foo_obj(foo_obj);
 foo_error:
+	kset_unregister(example_kset);
 	return -EINVAL;
 }