Bug1130 v1.2

Here's a PR for bug 1130 which is linked to a flow load-balancing issue in af_packet. It may be a partial fix as I did not manage to get successful testing when using cluster_cpu. But it is more likely to be a problem linked with packet load balancing on the network card.

Redmine ticket: https://redmine.openinfosecfoundation.org/issues/1130

PR builds:
- PR build: https://buildbot.suricata-ids.org/builders/regit/builds/122
- PR pcaps: https://buildbot.suricata-ids.org/builders/regit-pcap/builds/61