Proper deletes while iterating the SYNC keys collection
Proper deletes while iterating the SYNC keys collection

Make sure we don't increment an iterator pointed to a previously
deleted element - this is considered an unsafe operation.

Change-Id: I74da4a81a2dfb38cdc305ed970ab5b5ba7466c8a
Reviewed-on: http://review.membase.org/4807
Tested-by: Chiyoung Seo <8b279095f11c26cc21045fda5a3e51debb005aa9@gmail.com>
Reviewed-by: Chiyoung Seo <8b279095f11c26cc21045fda5a3e51debb005aa9@gmail.com>

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