Bug 1829: Add logging around failover and rebalance.
Bug 1829: Add logging around failover and rebalance.

This will show me when the user pushes failover and what nodes are
being passed as KeepNodes and EjectNodes to rebalance, because any
node not passed as one of these will not have its membership updated
at the end of rebalance.

Change-Id: I263a32244f97e960a76258b4abbe261ee23de3ec
Reviewed-on: http://review.northscale.com/1283
Reviewed-by: Aliaksey Kandratsenka <340b8e09ca65cd3fc686427fcfed17e87eaf61e2@gmail.com>
Reviewed-by: Steve Yen <ef850f73f7832052d3c6d9b5ddd3a1716d9a57f1@gmail.com>
Tested-by: Steve Yen <ef850f73f7832052d3c6d9b5ddd3a1716d9a57f1@gmail.com>

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