[BP]MB-7497: Remove dirtiness from stored value

Change-Id: Ie1e201469cf9d58aaf42c335e66c26bfa6ca7701
Reviewed-on: http://review.couchbase.org/25279
Reviewed-by: xiaoqin ma <maxiaoqin2005@gmail.com>
Reviewed-by: Michael Wiederhold <mike@couchbase.com>
Tested-by: Michael Wiederhold <mike@couchbase.com>