CBQE-0: plotter.py take into account all existed phases

Change-Id: I95bade5858a500fd99e814294083b6510e94c347
Reviewed-on: http://review.couchbase.org/28296
Reviewed-by: Andrei Baranouski <andrei.baranouski@gmail.com>
Tested-by: Andrei Baranouski <andrei.baranouski@gmail.com>