Allow time-bound based checkpoint creation for TAP consumer.
Allow time-bound based checkpoint creation for TAP consumer.

This change allows time-bound based checkpoint creation for TAP
consumer that does not enable checkpoint synchronization.

Change-Id: Ibb8e38d92a06ca89654d775859fd0473cc0d00c8
Reviewed-on: http://review.couchbase.org/6924
Tested-by: Chiyoung Seo <8b279095f11c26cc21045fda5a3e51debb005aa9@gmail.com>
Reviewed-by: Bin Cui <ed18693fff32c00e22495f4877a3b901bed09041@gmail.com>

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