MB-9715: Fixed the upr api to allow for "pause"

Change-Id: Ia4e772a64be253d1e81eae57746987bb8bdd437b
Reviewed-on: http://review.couchbase.org/30087
Reviewed-by: Trond Norbye <trond.norbye@gmail.com>
Tested-by: Trond Norbye <trond.norbye@gmail.com>