Fix to a bug in an incremental backup's ACK to the master server.
Fix to a bug in an incremental backup's ACK to the master server.

This fixes the wrong status code in the incremental backup client's
ACK message.

Change-Id: I5707cb149c73120a17e974cb1f536a088f82cc94
Reviewed-on: http://review.membase.org/5124
Tested-by: Steve Yen <ef850f73f7832052d3c6d9b5ddd3a1716d9a57f1@gmail.com>
Reviewed-by: Steve Yen <ef850f73f7832052d3c6d9b5ddd3a1716d9a57f1@gmail.com>

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