Create the backfill thread in detached state
Create the backfill thread in detached state

The pthread implementation we use on win32 doesn't support the
construct: pthread_detach(pthread_self());

Change-Id: Ifb0a5247b848f61ea0dac0b5ab4aeb93aa7f147d
Reviewed-on: http://review.northscale.com/1280
Reviewed-by: Dustin Sallings <1c08efb9b3965701be9d700d9a6f481f1ffec3ea@spy.net>
Tested-by: Dustin Sallings <1c08efb9b3965701be9d700d9a6f481f1ffec3ea@spy.net>

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