Exclude couchdb and mapreduce_errors loggers from ns_couchdb.log.
Exclude couchdb and mapreduce_errors loggers from ns_couchdb.log.

Because they can be very verbose.

Change-Id: Ie149410e0def7040534740e85c4b03f68182aa78
Reviewed-on: http://review.couchbase.org/55508
Tested-by: Aliaksey Artamonau <3c875bcfb3adf2a65b2ae7686ca921e6c9433147@gmail.com>
Reviewed-by: Artem Stemkovski <15a0730a27c69f62ab86f2b6c639fca202166c02@couchbase.com>

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