pfring: call enable_ring after set_cluster

Move pfring_enable_ring to the start of ReceivePfringLoop() so that
it's guaranteed to be called after all threads have called
pfring_set_cluster first.

This is necessary because pfring will already make packets available
to thread N, while thread N+1 is still registering itself. This leads
to cases where the first packet(s) of a flow are processed by a
different thread in Suricata than the later ones.

This is a race condition only at start up. New flows after the pfring
initialization is complete will not be influenced by this.

Bug #1129.
Fix live reload

Fix memsets clearing out of bounds memory on live reload, causing
crashes and corrupted backtraces.

Bug #1128.
eve-http: print <unknown> like in eve-files

When UA or Host are unknown, print <unknown> instead of <useragent
unknown> or <hostname unknown>.

Bug #1131.
eve-files: file -> fileinfo

Due to what appears to be an issue in logstash, the 'file' part of
the file event types was masked by a field that logstash-forwarder
added itself.

Since logstash-forwarder is an important part of the logstash stack,
this patch works around the issue by renaming our 'file' structure
to 'fileinfo', thus resolving the naming conflict.

Bug #1127
eve-file: set event_type to fileinfo

To remain constistent with the other logs, set the event type to
the same name as the structure containing the defails. In this
case fileinfo.

Part of bug #1127.
eve-http: register with app-layer api

The HTTP module of Eve didn't register itself with the app-layer
for HTTP. This meant that if no other HTTP logger was active, the
HTTP logging in Eve wouldn't work.

This patch makes the HTTP Eve module register itself correctly.

Bug #1133.