CBQE-2211 check status is not None before execute status.status
as show error in upgrade test 'NoneType' object has no attribute 'status'

Change-Id: I299a6edc6251fc51d883a5bbe6a80b2f9619f3c9
Reviewed-on: http://review.couchbase.org/36245
Tested-by: Thuan Nguyen <soccon@gmail.com>
Tested-by: buildbot <build@couchbase.com>
Reviewed-by: Thuan Nguyen <soccon@gmail.com>