builder/virtualbox: recognize <tab>
builder/virtualbox: recognize <tab>

smerrill/packer,zyegfryed/packer,Kaixiang/packer,suma/packer,TranscendComputing/packer,zyegfryed/packer,patricklucas/packer,TranscendComputing/packer,suma/packer,Kaixiang/packer,smerrill/packer,patricklucas/packer,msabramo/packer,suma/packer,zyegfryed/packer,Kaixiang/packer,TranscendComputing/packer,smerrill/packer,suma/packer,Kaixiang/packer,smerrill/packer,zyegfryed/packer,msabramo/packer,patricklucas/packer,msabramo/packer,TranscendComputing/packer,patricklucas/packer,msabramo/packer