Cleanup default_format initialization code

Change-Id: I4340962281a11195b906a2a02914c5af816c54e3
Reviewed-on: http://review.couchbase.org/26552
Reviewed-by: Volker Mische <volker.mische@gmail.com>
Tested-by: Mordechai Nunberg <mnunberg@haskalah.org>