Code to set the PATH in `install-msi.rb` causes chefspec to fail on non-Windows platforms

[mattstratton]

Cookbook version

4.2.0

Platform Details

MacOS
ChefDK 1.2.22

Scenario:

Attempting to include the default recipe from this cookbook in another cookbook, and then run default chefspec tests on that cookbook.

Steps to Reproduce:

1. create new cookbook with chef generate cookbook
2. depend on webpi.
3. add include_recipe 'webpi::install-msi' to default.rb.
4. run standard chefspec test.

Expected Result:

I expect no errors from chefspec

Actual Result:

[2017-04-24T18:31:10-05:00] ERROR: Unable to find Webpi executable
F

Failures:

  1) pi_test::default converges successfully
     Failure/Error: expect { chef_run }.to_not raise_error

       expected no Exception, got #<RuntimeError: WebpiCmd.exe can't be found> with backtrace:
         # /var/folders/v1/dp0988lj1tv15nmv63fby85c0000gn/T/d20170424-29440-1taq1qa/cookbooks/webpi/recipes/install-msi.rb:38:in `from_file'
         # /var/folders/v1/dp0988lj1tv15nmv63fby85c0000gn/T/d20170424-29440-1taq1qa/cookbooks/pi_test/recipes/default.rb:7:in `from_file'
         # ./spec/unit/recipes/default_spec.rb:23:in `block (2 levels) in <top (required)>'
         # ./spec/unit/recipes/default_spec.rb:26:in `block (3 levels) in <top (required)>'
         # ./spec/unit/recipes/default_spec.rb:26:in `block (2 levels) in <top (required)>'
     # ./spec/unit/recipes/default_spec.rb:26:in `block (2 levels) in <top (required)>'

Finished in 0.35951 seconds (files took 3.03 seconds to load)
1 example, 1 failure

[DJSablosky]

I also get this same error when using the default recipe for webpi from a workstation on Amazon Linux 2.