send errors from remote clusters correctly

Change-Id: I0cf8f863a61d571212e3170fd8727d2c3aedf1dc
Reviewed-on: http://review.couchbase.org/31366
Tested-by: Aliaksey Kandratsenka <alkondratenko@gmail.com>
Reviewed-by: Artem Stemkovski <artem@couchbase.com>