This is a tough one to unit tests because the behavior is tangled up in
the code that hits releases.hashicorp.com, so we'll add this e2etest as
some extra insurance that this works end-to-end.
We already have good tests for the business logic around provider
installation, but the existing tests all stub out the main repository
server. This test completes that coverage by verifying that the installer
is able to run against the real repository and install an official release
of the template provider.
James Bardin