ip-neighbor: fix show ip neighbor issue
ip-neighbor: fix show ip neighbor issue

Fix the issue that vppctl show ip4{6} neighbor [interface] command can't
show entries correctly, example: both ip4 and ip6 entries can be shown
with command:
vppctl show ip4 neighbor.

Type: fix

Signed-off-by: Michael Yu <5e54a91181cadd28b489bf5304d3325fcba8e215@nokia-sbell.com>
Change-Id: I229368b71cd285adce994c8290cc9d7e4c4f5aa6
Signed-off-by: Michael Yu <5e54a91181cadd28b489bf5304d3325fcba8e215@nokia-sbell.com>

chrisy/vpp,chrisy/vpp,FDio/vpp,chrisy/vpp,chrisy/vpp,chrisy/vpp,chrisy/vpp,FDio/vpp,FDio/vpp,FDio/vpp,chrisy/vpp,FDio/vpp,FDio/vpp,FDio/vpp,chrisy/vpp,FDio/vpp