NFV config: fix function load

 - pass t.port_id do virtio
 - create filter only if there are actually rules (# is >0)

Signed-off-by: Nikolay Nikolaev <n.nikolaev@virtualopensystems.com>
neutron2snabb: fix filter generation

 - we do not support filters based on remote_group_id, jsut drop those
 - return an empty list when there are no valid rules found

Signed-off-by: Nikolay Nikolaev <n.nikolaev@virtualopensystems.com>
snabbnfv-traffic: apply config on each internal iteration

Before it was 60 seconds - too slow

Signed-off-by: Nikolay Nikolaev <n.nikolaev@virtualopensystems.com>
Merge pull request #325 from virtualopensystems/misc_fixes

Misc fixes