Fix issue that caused items to be re-replicated through upr
Fix issue that caused items to be re-replicated through upr

We us the lowest sequence number in a checkpoint as the sequence
number for a checkpoint start message. During the setOpenCheckpointId
call we were resetting the sequence number to something higher and
this caused problems for sequence number replication. I also
refactored the sequence number registration so that we don't send
the item at the start sequence number.

Change-Id: Idc6555b09036c546fa58859947af09ca8100a38e
Reviewed-on: http://review.couchbase.org/34413
Tested-by: buildbot <80754af91bfb6d1073585b046fe0a474ce868509@couchbase.com>
Reviewed-by: David Liao <8e08c548e0b7af1f302000a438697daa6f52b5d5@couchbase.com>

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