(RK-393) Don't modify base module overrides

[tvpartytonight]

The base module class would modify the overrides supplied from
the puppetfile module loader; this ends up corrupting every
subsequent #add_module call. This change only reads that value
into the exclude_spec instance var for the module base class.

Please add all notable changes to the "Unreleased" section of the CHANGELOG in the format:

- (JIRA ticket) Summary of changes. [Issue or PR #](link to issue or PR)

[Magisus]

So this would have come out false before? Is that because we're passing a reference to the overrides hash rather than making a copy when we take it into the module/base class?

[tvpartytonight]

Not exactly; since the base module class deleted the key, the entire entry in the hash would be missing; if you run the test with the old code, you'll see this error message:

r10k: be rspec spec/unit/module_loader/puppetfile_spec.rb
............F............................

Failures:

  1) R10K::ModuleLoader::Puppetfile adding modules should not modify the overrides when adding modules
     Failure/Error: expect(subject.instance_variable_get("@overrides")[:modules]).to eq({exclude_spec: true})

       expected: {:exclude_spec=>true}
            got: {}

       (compared using ==)

       Diff:
       @@ -1,2 +1 @@
       -:exclude_spec => true,

     # ./spec/unit/module_loader/puppetfile_spec.rb:106:in `block (3 levels) in <top (required)>'

Finished in 0.07463 seconds (files took 0.46108 seconds to load)
41 examples, 1 failure

This means that the exclude_spec would end up as false for all remaining base class initializations.

[Magisus]

Huh okay. Wild.