MB-10415 use memcached password for moxi

Change-Id: Ic791096ba4b9fed498895a80d42f33329e94a142
Reviewed-on: http://review.couchbase.org/35427
Tested-by: Artem Stemkovski <artem@couchbase.com>
Reviewed-by: Aliaksey Kandratsenka <alkondratenko@gmail.com>