Ignore osx_defaults that may have been created by team already


I have the following scenario, the team defaults may be set at a higher level to the 'people::x' manifests. Though I want to maintain (carry with me) my set of configuration option. I don't care if its already defined, just ignore my custom osx setting and apply team level (ie: security settings).

This pull request ignores any osx_setting already set by the team manifests further up the tree, and allows me to set ignorable settings at my level.

I'm not sure of the best way to spec this (apologies if its completely wrong), but went for the earliest red/green. Not sure on the best way to call custom fixtures for the specific spec setup.

Cheers,

Tom