CBQE-363: prevent full disk messages for windows

Change-Id: I1c82c13be0e2099bd0d708b784d2cba0b3992027
Reviewed-on: http://review.couchbase.org/24501
Reviewed-by: Andrei Baranouski <andrei.baranouski@gmail.com>
Tested-by: buildbot <build@couchbase.com>