Apparently the idea to prefix a package with an underscore is not that
smart as I thought. Yes `go test` does not run it by default when you
run `go test ./...` but also other commands like `go mod tidy` do not
work consistently.
Nothing changes in practice. By default only unit tests run. Setting the
new environment variable: `TEST_WITH_VAGRANT` you include the test who
uses vagrant.
Signed-off-by: Gianluca Arbezzano <gianarb92@gmail.com>