ansible looks for group and host vars directories as well as playbooks
this revision to the provisioner uploads those as well.
squashed to a single commit by strcrzy.
allow users to provide a replacement command / extra args to the
ansible-local provisioner.
this is useful, for example, to unbuffer output when using the
docker builder, or to modify ansible behavior, like enabling
verbose mode, injecting variables, or changing paths.
`Provision` calls uploadFile on each path in playbook_paths, but
playbook_paths can only contain directories, per bf7530ca28.
This changes `Provision` to call uploadDir instead.