MB-4418: tap_throttle_queue_cap in cbflushctl takes 'infinite' argument
MB-4418: tap_throttle_queue_cap in cbflushctl takes 'infinite' argument

The infinite argument will map to -1 for the tap_throttle_queue_cap. We
are adding this mapping because in order for cbflushctl to be able to
parse -1 it would require doing '-- -1' and this is confusing and not
intuitive for ordinary users. Those who are familiar with the -- will
however still be able to use it.

Change-Id: I44b534d330a7cb7c9b132113b2cb0564901cfcfc
Reviewed-on: http://review.couchbase.org/15895
Tested-by: Chiyoung Seo <8b279095f11c26cc21045fda5a3e51debb005aa9@gmail.com>
Reviewed-by: Chiyoung Seo <8b279095f11c26cc21045fda5a3e51debb005aa9@gmail.com>
Reviewed-on: http://review.couchbase.org/16078

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