MB-6645 Fix to expiry_no_items_warmup unit test failure
MB-6645 Fix to expiry_no_items_warmup unit test failure

This unit test should make sure that the expiry pager runs once
before soft shutdown.

Change-Id: I0b97133cdb3442659b2e67ceb69199077b0ff6fc
Reviewed-on: http://review.couchbase.org/20841
Tested-by: buildbot <80754af91bfb6d1073585b046fe0a474ce868509@couchbase.com>
Reviewed-by: Chiyoung Seo <8b279095f11c26cc21045fda5a3e51debb005aa9@gmail.com>

daverigby/kv_engine,teligent-ru/ep-engine,abhinavdangeti/ep-engine,daverigby/kv_engine,jimwwalker/ep-engine,membase/ep-engine,sriganes/ep-engine,sriganes/ep-engine,jimwwalker/ep-engine,couchbase/ep-engine,owendCB/ep-engine,abhinavdangeti/ep-engine,daverigby/ep-engine,membase/ep-engine,couchbase/ep-engine,daverigby/kv_engine,couchbase/ep-engine,owendCB/ep-engine,membase/ep-engine,jimwwalker/ep-engine,hisundar/ep-engine,teligent-ru/ep-engine,daverigby/kv_engine,daverigby/ep-engine,abhinavdangeti/ep-engine,owendCB/ep-engine,daverigby/ep-engine,daverigby/ep-engine,sriganes/ep-engine,abhinavdangeti/ep-engine,owendCB/ep-engine,membase/ep-engine,hisundar/ep-engine,hisundar/ep-engine,couchbase/ep-engine,sriganes/ep-engine,teligent-ru/ep-engine,hisundar/ep-engine,teligent-ru/ep-engine,abhinavdangeti/ep-engine,jimwwalker/ep-engine