Design doc management fixes:

- _design_poll() should accept the 'devmode' argument
- design_publish() should invoke _design_poll() on the published view

Change-Id: I8434a323fb11f7010dfff01423b69b126396c103
Reviewed-on: http://review.couchbase.org/38814
Tested-by: Mark Nunberg <mnunberg@haskalah.org>
Reviewed-by: Volker Mische <volker.mische@gmail.com>