bc_cccp: Make it clear we're always using SASL

This change solidifies the existing behavior in that we always do SASL
auth.

Change-Id: I734f6be60f95a5931deb84650d46798072ba49a2
Reviewed-on: http://review.couchbase.org/34022
Reviewed-by: Brett Lawson <brett19@gmail.com>
Tested-by: Mark Nunberg <mnunberg@haskalah.org>