Terminate wating for warmup loop when warmup is complete

Change-Id: I42b7fcd0c3e072e1af2e29b34ee1254de8925294
Reviewed-on: http://review.couchbase.org/40573
Tested-by: buildbot <build@couchbase.com>
Reviewed-by: Tommie McAfee <tommie@couchbase.com>