Remove the VirtualBox warning while shutting down

While shutting down and stopping services, the one related to VirtualBox Additions appears as [WARNING!] when not running inside VirtualBox.

The error message is:

VirtualBox Additions disabled, not in a Virtual Machine. [WARNING!]

Some user have reported to be worried about that warning.

Implementation hints

This problem is twofold:

• detecting if we’re running inside VirtualBox (there is virt-what in Tails, that we’re using for similar needs)
• and if that’s not the case, making it so the virtualbox*
  initscripts are not run at shutdown/reboot time (that’s a job for
  update-rc.d).

The entire thing could be run via an initscript started
late in the boot process, e.g. after GDM.

Attachments

• disable-virtualbox2.txt

Related issues

• Related to #8082 (closed)

Original created by @sajolida on 7358 (Redmine)