netfilter: nfnetlink_queue: Solve the NFQUEUE/conntrack clash for NF_REPEAT

NF_REPEAT places the packet at the beginning of the iptables chain
instead of accepting or rejecting it right away. The packet however will
reach the end of the chain and continue to the end of iptables
eventually, so it needs the same handling as NF_ACCEPT and NF_DROP.

Fixes: 368982cd ("netfilter: nfnetlink_queue: resolve clash for unconfirmed conntracks")
Signed-off-by: Michal 'vorner' Vaner <michal.vaner@avast.com>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>