Bug1111

The first patch is a fix for bug 1111. The second converts the packets counter to 64bits integer to avoid a potential overflow on busy boxes.

Redmine ticket: https://redmine.openinfosecfoundation.org/issues/1111

PR builds:
- PR build: https://buildbot.suricata-ids.org/builders/regit/builds/110
- PR pcaps: https://buildbot.suricata-ids.org/builders/regit-pcap/builds/49