mbbackup-incremental -r flag to register name and exit
mbbackup-incremental -r flag to register name and exit

Allows the user to register a TAP name, likely to be used later in a
following mbbackup-incremental session.

Change-Id: Iacd9778896a4fb2ee06d814dc306cf0e14b48810
Reviewed-on: http://review.membase.org/5054
Reviewed-by: Chiyoung Seo <8b279095f11c26cc21045fda5a3e51debb005aa9@gmail.com>
Tested-by: Chiyoung Seo <8b279095f11c26cc21045fda5a3e51debb005aa9@gmail.com>

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