Puppet: no color output on Win; vbox detection

Command Prompt on Windows has poor support for ANSI escape sequences, causing
Puppet's output to appear garbled. This patch makes Puppet run with
"--color=false" on Windows hosts.

Also fixes VirtualBox version detection by adding a check to ensure the version
string is sane before writing it to /etc/virtualbox-version.

Change-Id: I95e898fb556c1e5d1d45efaf966ca04345c149a8