Initial storage api work
host: use storage api
storage: allow preallocated storage
Add Host specific wrapper to StorageRegister()
Move Host Tag storage to Host Storage API.
Storage API: add registration check closed test in debug mode.
Init storage api at start up
Use Host Storage API for per host thresholding
Host: use global free storage function

This patch is here to avoid that all modules using a local storage
have to update host code to add their free function. It modifies
previous behavior by calling HostFreeStorage in any case.
Add per-flow generic storage

This patch adds a per-flow storage that can be created via the functions
available in flow-storage.c.
flow tag: conversion to flow storage API

This patch is updating the flow tag system to use the flow
storage API. The tag_list member of Flow structure is suppressed
and its cleaning operation are suppressed too as this is handled
transparently by the flow storage API.
engine-tag: rename var and add sanity check
Storage API: add safety check for cases when there is no storage used.
Storage: rename Init to Alloc to reflect actual functioning. Comment updates.