Don't error out a VMware run if there is a seconary NIC

Under VMware we cannot read MAC addresses so this was throwing an error, to avoid that we skip trying to configure secondary adapters and instead print out a warning telling the user they'll have to do it themselves.
Use latest Vagrant release for development
Fixed WinRMExecutionError declaration

Change all config vars to @config
Need to return the correct exitcode from the last command run in PowerShell

This is needed because otherwise PowerShell only returns a True or False value which is really annoying when you have detailed exit codes turned on with Puppet