os_env resource returns only user's environment variable on Windows

[omar-irizarry]

Enhance os_env resource to deal with scenario explained in issue #2940

os_env resource may be called with one parameter, this keeps the current functionality

describe os_env('variablename') do
  its('content') {should eq 'content' }
end

os_env resource may be called with two parameters

describe os_env('variablename', 'target') do
  its('content') {should eq 'content' }
end

target values may be system or user

[jquick]

Thanks @omar-irizarry! This is a great enhancement. Would you mind adding an example here?https://github.com/chef/inspec/blob/master/docs/resources/os_env.md.erb

[clintoncwolfe]

There's a conditional in there that is, um, unorthodox, but it's sounds. I tested it on win2016 on an EC2 instance, all's well. Thanks @omar-irizarry !

[clintoncwolfe]

An inline unless with a block dual-arm if block. Yes!