MB-7907: add config with disabled auto-compaction

Change-Id: Iafaff26b34414bb95b0ce1bd8c545924abbb598a
Reviewed-on: http://review.couchbase.org/25330
Reviewed-by: Pavel Paulau <pavel.paulau@gmail.com>
Tested-by: Pavel Paulau <pavel.paulau@gmail.com>