Clustering : Connecting 2-node mininet causes the controller to run out of memory

when mininet is connected to the controller, all heap memory is consumed within a few minutes (7 on a Mac-OSX). This is likely caused by flushing journals to disk every 20k logs. If logs are huge (as with stats collection running), the 20k threshold is never reached and all the journals appear in the OldGen memory.

We also need to flush journals when a certain memory threshold is reached.