CCBC-399: Promote logging API to uncommited

Change-Id: Ieabe3dafd3780b61411c2b1bfbad4e46427d8c83
Reviewed-on: http://review.couchbase.org/37801
Tested-by: Mark Nunberg <mnunberg@haskalah.org>
Reviewed-by: Brett Lawson <brett19@gmail.com>