Add shell_out_with_systems_locale to ShellOut

In the spirit of moving away from Command in favor of ShellOut, I've included a `shell_out_with_systems_locale`, which mimics the behavior of `run_command_with_systems_locale`.

Once this is merged, https://github.com/opscode/chef/pull/1532 can be updated to use ShellOut (I have already done that work and have manually verified the changes work on Debian 7).

\cc @opscode/client-eng 
maybe more like this?

```ruby
if args.last.is_a?(Hash)
  options = args.last
  option_key =  options.has_key?(:env) ? :env : :environment
  options[option_key] ||= {}
  options[option_key]['LC_ALL'] ||= nil
end
```

that sorta compiles in my head, but my parser is way more DWIM than ruby's...

and if someone passes in both :env and :environment with LC_ALL set only in the :environment option then they get what they deserve...

i'd sorta suggest we should deprecate one or the other of these, and you just should `raise if options.has_key?(:env)` (or whichever one draws the short straw).