Comment 13 for bug 1618899

Updating sudoers.tmpl causes templating problems with Cheetah instead, unfortunately.

What has worked for me is to patch vmbuilder to not touch /etc/sudoers at all. There seems to be no need for it to do so, and you end up with the proper version of sudoers in the vm - no template required.

Patch attached to fix a running system, tested on trusty. It simply comments out one line in this file:
/usr/lib/python2.7/dist-packages/VMBuilder/plugins/ubuntu/dapper.py