Don't send a disk backfill item that is soft-deleted.
Don't send a disk backfill item that is soft-deleted.

Change-Id: I2f4db5e44cd4bf07e6b4b9b9c20381d71f886ddf
Reviewed-on: http://review.couchbase.org/12590
Reviewed-by: Michael Wiederhold <a17fed27eaa842282862ff7c1b9c8395a26ac320@couchbase.com>
Tested-by: Chiyoung Seo <8b279095f11c26cc21045fda5a3e51debb005aa9@gmail.com>

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