Fix the compilation warning in checkpoint
Fix the compilation warning in checkpoint

Change-Id: I88c1510797f53107cd35de529edae657bd1d0da8
Reviewed-on: http://review.couchbase.org/46395
Reviewed-by: Trond Norbye <60edd2ef23891a753f231b0c6f161dc634079a93@gmail.com>
Tested-by: Chiyoung Seo <fcffc23db27b19ee4ebba46695ee6b50e09216a2@couchbase.com>

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