correctly handle disabled by default events in POST /settings/audit
correctly handle disabled by default events in POST /settings/audit

We assume that caller knows complete list of filterable events and all
events not submitted as disabled are enabled regardless of their
defaults. Defaults really make any difference only in GET /settings/audit
and only when new filterable event appears that was never overwritten
by POST

Change-Id: Icaa1f8586676b1447c59897d157b88ad89f43593
Reviewed-on: http://review.couchbase.org/89310
Reviewed-by: Aliaksey Artamonau <ce14b1c16e0fd654f926118eb8addbec5aff4ffa@couchbase.com>
Well-Formed: Build Bot <80754af91bfb6d1073585b046fe0a474ce868509@couchbase.com>
Tested-by: Aliaksey Artamonau <ce14b1c16e0fd654f926118eb8addbec5aff4ffa@couchbase.com>

membase/ns_server,membase/ns_server,membase/ns_server,membase/ns_server,membase/ns_server,membase/ns_server