* Fix FactCache to conform to the dict API
* update needs to take a dict rather than a key and a value
* __init__ needs to allow for setting the intial dictionary
* Remove unneeded _display and _cache attributes
* Move ansible.plugins.cache.FactCache to
ansible.vars.fact_cache.FactCache because this isn't part of the cache
plugin API.
* Add backwards compatibility when calling update on the new FactCache
* Remove code for calling old FactCache. There's no way to call the old
FactCache so there's no need for backwards compatible code for calling
code. Backwards compatibility is handling things which are calling
the new FactCache.
* Port our code to the new FactCache location.
