CBD-1354:  need to call last_done_server() to get its status

Change-Id: I43e1791655971ac02228b54da7e29a29ce1e846a
Reviewed-on: http://review.couchbase.org/36151
Reviewed-by: Philip Labee <philip@couchbase.com>
Tested-by: Philip Labee <philip@couchbase.com>