CBQE-0: py-xdcr-unidirectional.conf with diff buckets

Change-Id: I3496e72a095ed7d27a581f49ee59bbf03cf50a07
Reviewed-on: http://review.couchbase.org/33387
Reviewed-by: Andrei Baranouski <andrei.baranouski@gmail.com>
Tested-by: Andrei Baranouski <andrei.baranouski@gmail.com>