iftable: fix wrong handler unregistration on error

Need to unregister the ifadd_handler in err_unregister instead of
unregistering ifdel_handler.

Signed-off-by: Andrey Kuzin <kuzinandrey@yandex.ru>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
1 file changed