CBQE-1069: wait until upgrademe is complete for windows

to avoid timeouts when windows upgrade is more slower with big data

Change-Id: Ib2859bdb3994b4b5bd29b6ceb0a005ba866c7f05
Reviewed-on: http://review.couchbase.org/25122
Tested-by: buildbot <build@couchbase.com>
Reviewed-by: Andrei Baranouski <andrei.baranouski@gmail.com>