Remove Kraken-specific varnishncsa instance

I confirmed with Andrew Otto that this is not being used. I think the original
idea there was that the stream would go to Hadoop. But the value provided by
EventLogging stems from the strict validation of events w/reference to declared
data models, so bypassing EventLogging doesn't really make sense. I'd still
like to see the scrubbed / parsed / validated event stream land in Hadoop, but
would be coming from EventLogging (vanadium), not Varnish.

Change-Id: I74d52f89c46c461e2b70c0d8f84fa95bd1cc82e5