MB-4513: Don't eject partial items on insert
MB-4513: Don't eject partial items on insert

ep-engine was failing during the first phase of warmup because
we were ejecting values that weren't even in memory yet (partial
items). This fix makes it so that we don't eject partial items.

Change-Id: Icffed5697eb9ba8f3ea925bbb770802004528123
Reviewed-on: http://review.couchbase.org/11570
Reviewed-by: Michael Wiederhold <a17fed27eaa842282862ff7c1b9c8395a26ac320@couchbase.com>
Tested-by: Michael Wiederhold <a17fed27eaa842282862ff7c1b9c8395a26ac320@couchbase.com>

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