MB-5904 Filter out password for email alerts too.

Change-Id: I5cbba952e647d4eb75914d86f3e98e6c8c184024
Reviewed-on: http://review.couchbase.org/28412
Tested-by: Aliaksey Artamonau <aliaksiej.artamonau@gmail.com>
Reviewed-by: Aliaksey Kandratsenka <alkondratenko@gmail.com>