New ohai hints feature allowing the creation hints.

Example:
machine "blah" do
  ohai_hint 'ec2' => {}, 'digitalocean' => {}
end
Updated to use action_handler instead of provider.
Mkdir recursively.
Renamed ohai_hint to ohai_hints
Merge branch 'ohai_hints' of git://github.com/xorl/chef-metal into xorl-ohai_hints

Conflicts:
	lib/chef_metal/machine/unix_machine.rb