network.cookie.enableForCurrentSessionOnly has been replaced by network.cookie.lifetimePolicy. We should remove it. The Opera profile migrator is currently migrating an Opera pref into this pref, and I've filed bug 337231 to correct this behaviour. I'm not sure if removing this while the migrator is still using it would bust the migrator, so I'll hold off on the patch until that's fixed or until I hear otherwise.
Created attachment 289115 [details] [diff] [review] one instance tough patch!
Comment on attachment 289115 [details] [diff] [review] one instance trivial cleanup patch.