changed mapping of release_upgrades_policy causes software-properties-kde to set the wrong policy

[Impact]
At some point the release upgrade policy mapping has changed which causes this behaviour in the KDE UI:

UI: Update-manager:
Never -> Normal
Normal -> LTS
LTS -> Never

I found this after a user complained that do-release-upgrade -d on oneiric didn't find the precise upgrade which was in fact the user setting the notification policy to LTS by mistake, and software properties storing that as Never internally so this is at least broken since 11.10 and needs an SRU for kubuntu upgrades to work right.

A simple fix for oneiric would be to simply shift the mapping with (i +/- 1) % 3, but that's not much of a proper fix.

[Test Case]
1) open software-properties-kde
2) In the Updates tab change the policy for release upgrades that should be shown
3) open /etc/update-manager/release-upgrades
4) verify that prompt is set to something different than what was set in the GUI
5) install package from precise-proposed
6) repeat steps 1-3
7) verify that prompt is now set to the right value

[Regression Potential]
None, this is already broken and the change only touches the broken part.

ProblemType: BugDistroRelease: Ubuntu 12.04
Package: software-properties-kde 0.82.4 [modified: usr/share/pyshared/softwareproperties/kde/SoftwarePropertiesKDE.py]
ProcVersionSignature: Ubuntu 3.2.0-17.27-generic 3.2.6
Uname: Linux 3.2.0-17-generic x86_64
ApportVersion: 1.93-0ubuntu2
Architecture: amd64
Date: Fri Mar 2 15:59:28 2012
InstallationMedia: Kubuntu 11.10 "Oneiric Ocelot" - Beta amd64 (20111007)
PackageArchitecture: all
ProcEnviron:
 SHELL=/bin/bash
 TERM=screen
 PATH=(custom, user)
 LANG=en_US.UTF-8
 LANGUAGE=en_US.UTF-8SourcePackage: software-properties
UpgradeStatus: No upgrade log present (probably fresh install)