CBQE-887: Observe with warmup test case issue fix

Change-Id: Icb7bb91fe6c054db6d65cb0422d2dea270858692
Reviewed-on: http://review.couchbase.org/23704
Tested-by: buildbot <build@couchbase.com>
Reviewed-by: Rohit Sinha1 <rohit.sinha1@globallogic.com>
Tested-by: Rohit Sinha1 <rohit.sinha1@globallogic.com>