Comment 48 for bug 951000

I've verified lightdm 1.6.0-0ubuntu3 on raring and lightdm 1.2.3-0ubuntu2.3 on precise. This SRU looks good.

Test steps:
1. apt-get update
2. apt-get dist-upgrade
3. enable raring-proposed (or precise-proposed)
4. apt-get install lightdm
5. logout
6. login as guest
7. make sure ctrl-alt-L has no function and menu indicator does not have a "Lock screen" entry.
8. logout
9. repeat step 6-8 10 times.