vl: Don't include vde header

Nothing in vl.c uses anything from the vde package, do remove the
unnecessary include.

Signed-off-by: Fam Zheng <famz@redhat.com>
Message-Id: <20170907083552.17725-2-famz@redhat.com>
Reviewed-by: Jason Wang <jasowang@redhat.com>
Signed-off-by: Fam Zheng <famz@redhat.com>