* Replace terraform modules with github.com/hashicorp/terraform-exec.
* Remove all terraform providers.
* Remove all unneeded replaces.
* Tidy up the replace stanzas so that it is more clear why each replace is needed.
* Remove and re-create all indirect requires to clean up ones that are
no longer needed.
Also had to manually add vfsutil to testImports because glide didn't
pick it up for some reason.
Commands run:
rm glide.lock
glide install --strip-vendor
glide-vc --use-lock-file --no-tests --only-code
