CBQE-1069: adjust off_cl_upgr_non_default_path for windows

Change-Id: Icc6ee80c1efc3a8a8ad488ee90c1dfb440549414
Reviewed-on: http://review.couchbase.org/25158
Tested-by: buildbot <build@couchbase.com>
Reviewed-by: Andrei Baranouski <andrei.baranouski@gmail.com>