Fix error while compiling using 'vlib/vlib.h' dependencie.
Fix error while compiling using 'vlib/vlib.h' dependencie.

This variable without any needed 'define' becoming unused.

Change-Id: I661a75a78dba03abb861ed918ad1e634a8ecd0af
Signed-off-by: Dmitry Vakhrushev <a8cf97adadec4e1b734a39bc5aea71b5741cfca1@netgate.com>

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