Fix to the checkpoint unit test failure.
Fix to the checkpoint unit test failure.

The checkpoint unit test should make sure that the persistence
cursor processes all the items from the checkpoint datastructure
at the end of the test.

Change-Id: I2ecf6f53b7edbd0d2409d8d4d2c5d7d956b0851e
Reviewed-on: http://review.couchbase.org/7076
Tested-by: Chiyoung Seo <8b279095f11c26cc21045fda5a3e51debb005aa9@gmail.com>
Reviewed-by: Trond Norbye <60edd2ef23891a753f231b0c6f161dc634079a93@gmail.com>

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