vcl: fix compiling on newer systems
vcl: fix compiling on newer systems

Build fails on ubuntu 17.10...

Change-Id: I98dfffa3f8f5f9bca2ba97a856709714fbeec49c
Signed-off-by: Damjan Marion <9141bba8b2efed526e55cf796d48631af330ad98@cisco.com>

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