netfilter: nf_nat: fix action not being set for all ct states

This fixes openvswitch's handling of nat packets in the related state.

In nf_ct_nat_execute(), which is called from nf_ct_nat(), ICMP/ICMPv6
packets in the IP_CT_RELATED or IP_CT_RELATED_REPLY state, which have
not been dropped, will follow the goto, however the placement of the
goto label means that updating the action bit field will be bypassed.

This causes ovs_nat_update_key() to not be called from ovs_ct_nat()
which means the openvswitch match key for the ICMP/ICMPv6 packet is not
updated and the pre-nat value will be retained for the key, which will
result in the wrong openflow rule being matched for that packet.

Move the goto label above where the action bit field is being set so
that it is updated in all cases where the packet is accepted.

Fixes: ebddb140 ("net: move the nat function to nf_nat_ovs for ovs and tc")
Signed-off-by: Brad Cowie <brad@faucet.nz>
Reviewed-by: Simon Horman <horms@kernel.org>
Acked-by: Xin Long <lucien.xin@gmail.com>
Acked-by: Aaron Conole <aconole@redhat.com>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>