PYCBC-228: Place persist_to and replicate_to in order

Change-Id: I1716b1ebd6ff366cf64f06dc8b5aa7ef924c9665
Reviewed-on: http://review.couchbase.org/33489
Reviewed-by: Volker Mische <volker.mische@gmail.com>
Tested-by: Mark Nunberg <mnunberg@haskalah.org>