Clean log

Hey, I just tweaked your plugin a little bit to disable logging during OTR sessions.

The previously set logging level is restored after the OTR session is closed.


If someone wants to be a f***** a**hole and re-enable logging during an *OFF*-the-record conversation, he can still do so manually without breaking anything. But defaulting to disabling the logs makes a lot more sense.

Please merge it, we really need to start being responsible about logging.