Disable VirtualBox USB2.0 controller

This should make it possible to use the box without having the Extension Pack
installed.
Merge pull request #5 from rhafer/no-extension

Disable VirtualBox USB2.0 controller
Add another NIC to the box

We're using teaming by default now. So we need two NICs for the admin network.
Fix controller's network config

- Addtional Interface for bonding
- add ifcfg file for the admin network to the kiwi image
- disable default folder sync
Only add a single CPU to each VM

Most user will probably not have quad core machines and we're starting enough
VMs to keep the system busy anyhow.
Run crowbar_register on the controller

This requires some fixes to the provisioner barclamp:
- Some of our repos are unsigned call zypper ref with --no-gpg-checks
- crowbar_register doesn't work when the admin network is not on eth0
  (https://github.com/crowbar/barclamp-provisioner/pull/302)