Add Logging to Memory Leak Plug

It behaves differently in Prod would you believe.
Effect should be that there is no longer a thread local in the finalizer thread.


MAT finalizer overview locally:
![image](https://cloud.githubusercontent.com/assets/1722550/5319387/c62800c2-7ca0-11e4-843e-9d815a45c6aa.png)


on Prod:
![image](https://cloud.githubusercontent.com/assets/1722550/5319400/e6ccf274-7ca0-11e4-92f4-2d15b5fd5d6c.png)