## Changes
Auth relied on setting a profile. In this change we enumerate all
configuration properties and export all non-empty ones as a map with
environment variables. We then pass this map to the Terraform execution
wrapper.
This results in Terraform using the bundle's authentication
configuration.
This change is needed to make #287 work.
## Tests
Manually.
Users can opt out and use the system-installed version with the
following configuration:
```
bundle:
terraform:
exec_path: terraform
```
This will find the binary in $PATH and replace it with the found value.
If this is not set, the initialize phase will install Terraform in the
bundle's cache directory.
Pieter Noordhuis