ebaf17b8b5
puppetlabs_spec_helper recommends rspec-mocks instead of mocha[1] and
it uses rspec-mocks by default instead of mocha since v 5.0.0[2]
This is the prep work to adapt to that migration.
[1] https://github.com/puppetlabs/puppetlabs_spec_helper/#mock_with
[2] 493f0cbc1c
Closes-Bug: #2004135
Change-Id: I5e822f07c79fe16baee90eebd557ee8d7ed1237d