MB-10415 kill moxi in case of auth failure during the config retrieve

... so ns_server can restart it with the correct auth token

Change-Id: Ifac860f09850e357747760e59f03879fd8af2eca
Reviewed-on: http://review.couchbase.org/34959
Tested-by: Artem Stemkovski <artem@couchbase.com>
Reviewed-by: Aliaksey Artamonau <aliaksiej.artamonau@gmail.com>