builder/virtualbox: Output VBoxManage stderr in error
builder/virtualbox: Output VBoxManage stderr in error

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