[NETFILTER]: ipt_CLUSTERIP: fix non-existant macro-name

With nf_conntrack DUMP_TUPLE got renamed to NF_CT_DUMP_TUPLE, fix
CLUSTERIP to use the proper macro name.

Signed-off-by: Patrick McHardy <kaber@trash.net>
Signed-off-by: David S. Miller <davem@davemloft.net>