For the same reason the disco tests need to override the http.Transport,
other test fixtures will need to as well. Provide a field to override
the default httpTransport.
Update all references to the version values to use the new package.
The VersionString function was left in the terraform package
specifically for the aws provider, which is vendored. We can remove that
last call once the provider is updated.
Although service discovery metadata is usually not sensitive, a service
host may wish to produce different results depending on the requesting
user, such as if users are migrating between two different implementations
that are both running concurrently for some period.
This package implements our Terraform-native Service discovery protocol,
which allows us to find the base URL for a particular service given a
hostname that was already validated and normalized by the svchost package.