[dev] Update tasks clearing all memcache

[Gonçalo Queirós]

I there list.

Found today that using memcache for js, css and session at the same time 
was producing a very odd behavior.
The problem was that every time a user logged in, the Upgrade task from 
Horde run, and all memcache got cleared, thus making every single user 
to log off.

I don't know if this is the expected behavior, but to me it seems that 
its not.
Regarding the login/upgrade/system tasks, is there any way to configure 
which ones will run, or do i need to comment/remove the code from the 
ones i don't wan't to run ever?

Thanks,
Gonçalo Queirós