NAT: fix bin API dump of static mappings.
NAT: fix bin API dump of static mappings.

Static mappings with equal local and external IPs
but different ports were dumped as identity mappings.

Change-Id: Ifea7cef5b78aea4c2eb31cf1620185eeef2681e5
Signed-off-by: Milan Lenco <fd44239370131ad5b8cae55d5f197286407fee30@pantheon.tech>

chrisy/vpp,vpp-dev/vpp,FDio/vpp,chrisy/vpp,chrisy/vpp,vpp-dev/vpp,FDio/vpp,vpp-dev/vpp,vpp-dev/vpp,FDio/vpp,vpp-dev/vpp,chrisy/vpp,vpp-dev/vpp,FDio/vpp,chrisy/vpp,vpp-dev/vpp,FDio/vpp,FDio/vpp,chrisy/vpp,FDio/vpp,chrisy/vpp,chrisy/vpp,FDio/vpp