Kubuntu 13.04 and immediate screen blanking after upgrade

Upgrading from Kubuntu 12.10 to Kubuntu 13.04 is a less-than completely smooth experience. I'll skip any niceties and dig right into the problems.

Screen lock problems

I don't want to spend a lot of time debugging this, but it doesn't even appear possible to shut off the screen blanker so I have to do something. My google-fu is completely overwhelmed by another screenlock bug in KDE 4.10 that appears to lock the screen if you tell it to blank but not lock the screen.

This is not my problem. My problem is that the screen locker appears not to be able to tell time. If I'm idle for more than about 15 seconds, the screen locks. Suffice it to say, this gets annoying really quickly.

The dirty hack

Here's what I've done to fix the issue, and to completely confuse myself the next time the package gets upgraded:

mv /usr/lib/kde4/libexec/kscreenlocker_greet /usr/lib/kde4/libexec/kscreenlocker_greet.old

I welcome real solutions in the comments.