Support for newer versions of virtualbox

[kalinchernev]

This error is present when using 5.0.14 r105127

Vagrant has detected that you have a version of VirtualBox installed
that is not supported. Please install one of the supported versions
listed below to use Vagrant:

4.0, 4.1, 4.2, 4.3

Update: after upgrading vagrant to 1.8.1 the provisioning went through, but the vagrant folder is empty when ssh-ing into the vm. So, the versions seem to be problematic.