Ips stats v1.1

Here's a fix for ticket 1115. It fixes exit stats for NFQ and ipfw.

Redmine tickets:
- https://redmine.openinfosecfoundation.org/issues/1115
 
PR builds:
- PR build: https://buildbot.suricata-ids.org/builders/regit/builds/111
- PR pcaps: https://buildbot.suricata-ids.org/builders/regit-pcap/builds/50