CBQE-928: fix upgrade test with ports

Change-Id: Idcc499ce9d014a9a9d1102c8c4f4942ecfe1add1
Reviewed-on: http://review.couchbase.org/24544
Tested-by: Iryna Mironava <irynamironava@yandex.ru>
Tested-by: buildbot <build@couchbase.com>
Reviewed-by: Andrei Baranouski <andrei.baranouski@gmail.com>