Comment 18 for bug 877631

I've uploaded the fix from trunk/precise to oneiric-proposed and subscribed ubuntu-sru. This is a good SRU candidate because for some common locales, backup does not work after being interrupted.

For reproduction steps and background, see comment #16.

This fix prevents this sequence of events from happening in the future, but it does not try to automatically delete any data on your backend that may be cause the error now. So if you've hit this in the past, you may want to manually delete the old backup chain.