route-table-bsd: Update vlog.h inclusion

This fixes a build failure introduced by the recent vlog change
commit e6211adce42c28453e0004c7a3e342a3d52bb97d.
("lib: Move vlog.h to <openvswitch/vlog.h>")

Signed-off-by: YAMAMOTO Takashi <yamamoto@valinux.co.jp>
Acked-by: Thomas Graf <tgraf@noironetworks.com>