[provisioners/chef] Support Chef Solo local mode

The original intent here was to add `node_path` support so that I would be able to load up, using [Chef Solo configuration](http://docs.opscode.com/config_rb_solo.html), a node from the appropriate JSON files. Right now this seems to be limited by [how the nodes are loaded in Chef](https://github.com/opscode/chef/blob/master/lib/chef/client.rb#L346) but I have been tweaking some custom solo.rb  files and passing them into chef-solo and chef-client. 

The local mode, assuming Chef zero, seems to work fine. I did not want to go the route of knife-solo loading from data bags. So I started hacking around a bit and found that chef-client in local mode could be used to provision without a Chef Server.