Call FDB table cleaning tool from ocf script.

* Installs ssh keys to allow access between all computes and controllers
* add fuel-fdb-cleaner to neutron-agent-l3 OCF script

Change-Id: If855247a9654763b35dcd7adc5bfcf28d1fa331d
Closes-Bug: #1260465
Merge "Call FDB table cleaning tool from ocf script."