rebuild ns_config_ets_dup after online upgrade

Change-Id: Ib6870aa10ed7fbdbe60ef4cd49aa5d8636790b15
Reviewed-on: http://review.couchbase.org/37011
Reviewed-by: Aliaksey Kandratsenka <alkondratenko@gmail.com>
Tested-by: Aliaksey Kandratsenka <alkondratenko@gmail.com>