Allow chef-solo to use remote_file and other resources through proxy

[scotthain]

Allows passing of http_proxy, https_proxy, and no_proxy variables to the chef-solo solo.rb file by adding the following variables to .kitchen.yml:
chef_http_proxy: http://myproxy.com:8000
chef_https_proxy: http://myproxy.com:8000
chef_no_proxy: ".internal.corp,10."

[scotthain]

As an FYI, I chose to add new variables as opposed to using the existing http_proxy and https_proxy variables due to the fact that this is Chef-solo specific, and to the best of my knowledge Vagrant doesn't support (or need?) the no_proxy option. It seemed cleaner to keep it provider agnostic and add new variables rather than overloading the 'purpose' of the existing ones.

[sethvargo]

I think these might be better served in a nested hash:

chef
  http_proxy: #...

What do you think?

[scotthain]

I like it, that adds a layer of indirection that makes it more extensible for different providers in the future. I'll try and get that put together today or tomorrow.

[sethvargo]

@scotthain awesome thanks. Ping me when you do. Do you have a signed CLA with Opscode?

[scotthain]

@sethvargo got the CLA in order and just checked in the config refactor. cheers!

[programmerq]

This would be super useful for us as well. Gotta "love" those corporate proxies. :)

[sethvargo]

Merged in a29b476

[esciara]

Changes in this pull deprecated by commit 6e30431. See comments under that commit.