#1 Cookie file of the live classroom module in not thread safe

[Hugues Pisapia]

There is currently only one cookie file used by the LC module for the Lc
authentication.
It creates a race condition when two people will access the LC module at
the same time.

We should use a temp name for each of these, but also manae to remove
them... or have a poll of such files... I'm not sure about how to perform
this.