vlib: fix coverity warning
vlib: fix coverity warning

Remove now unused computation result.

Type: fix
Fixes: 3f8b8d30cade20afa8975a5e7a6d79346cec8f3e
Signed-off-by: Klement Sekera <b8003f27414ca85c37624503b7b4e8f8c829bb4d@cisco.com>
Change-Id: Iea142cb044d31e364fdc5b8b6dd69681e77d745f

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