Add the squeeze-lts distribution to sources.list for squeeze systems.
This is the long-term support archive, which provides extended
security support.

This was only missing because our mirror script didn't know about
it.  That's now been fixed, so add wheezy-updates back into the
default sources.list for wheezy.

Remove some comments that don't make sense in the generated file.

This is the (old) master branch along with the fixes to the
cron file permissions that Russ made.