turn on vmtoolsd on the start of boot2docker

by default start vmtoolsd at the init to boot2docker vm so that vSphere can get its IP address, and some other vm information.
It's probably better to start vmtoolsd with the --background option:
/usr/bin/vmtoolsd --background /var/run/vmtoolsd.pid
This is how it's started in the startup script for Ubuntu.