Before, the tempfile "f" could be GC'd before the path was used,
resulting in failed tests because when it is GC'd the tempfile is
removed. We now store the tempfile in an instance variable so that it
isn't even available for GC until after the test is finished running.
Tests before were picking up a Vagrantfile in the Vagrant source
directory, which can cause some funny failures. This ensures that each
test run will actually establish a new temporary CWD so that a
Vagrantfile is hopefully never found.
Config::Loader will be the new class responsible for loading configuration
and replaces the previous dual-role "Vagrant::Config" played. While this
commit is very early-stage, once this new architecture is flushed out, it
will make loading, using, and extending configuration much easier and cleaner.
Additionally, I believe this will help post Vagrant 1.0 if multi-language
configuration is implemented.