CBQE-1707: fix potentional issue in ViewQueryVerificationTask.check

test hangs http://qa.sc.couchbase.com/job/centos_x86--09_01--view_query-P0/9/consoleFull

Change-Id: I581d54ab58a26ef96b6dae2bcf5128ac69d5e543
Reviewed-on: http://review.couchbase.org/30381
Reviewed-by: Andrei Baranouski <andrei.baranouski@gmail.com>
Tested-by: Andrei Baranouski <andrei.baranouski@gmail.com>