added gathering control to ansible, 

As talked here:
https://groups.google.com/forum/#!msg/ansible-project/lGrvGwKuENU/-MNfmPBUHY4J

Before 1.5 fact gathering was 'magically smart' if you had gathered facts and you did not explicitly force fact gathering ansible would reuse the cache and avoid running fact gathering again. Striving for correctness and 'less magic' and unintended consequences, this was removed in 1.5.

This adds it back making it more visible and controllable by users through configuration.