Do not tag outputs with VLANs for SFC

this otherwise leads to packets being wrapped within 802.1Q packets,
which do not get popped before forwarding to a service. Thus, services
do not respond to ARP, PING and alike.

Change-Id: I7f29b5094f9bd33661e8f2862c8656c0f9a08a6b
Signed-off-by: schillinge <ablu@mail.uni-paderborn.de>