[NETFILTER] ipt_ULOG: Mark ipt_ULOG as OBSOLETE

Similar to nfnetlink_queue and ip_queue, we mark ipt_ULOG as obsolete.
This should have been part of the original nfnetlink_log merge, but
I somehow missed it.

Signed-off-by: Harald Welte <laforge@netfilter.org>
Signed-off-by: David S. Miller <davem@davemloft.net>