flow: fix flow logging at shutdown

Move all flows from the hash to the recycler at shutdown.

Bug #1260

Prscript:
- PR build: https://buildbot.openinfosecfoundation.org/builders/inliniac/builds/28
- PR pcaps: https://buildbot.openinfosecfoundation.org/builders/inliniac-pcap/builds/28

Replaces: #1140