debian: no prompting on update
debian: no prompting on update

sjfloat/mirage-vagrant-vms,mirage/mirage-vagrant-vms,englishm/vagrant-xen,mirage/mirage-vagrant-vms,yifanz/mirage-vagrant-vms,sjfloat/mirage-vagrant-vms,yifanz/mirage-vagrant-vms,englishm/vagrant-xen