MB-8863: improved ROUser created message

Change-Id: Ibbbed603bf8ca1c4ae4e8f3ba6e5656923ad69d3
Reviewed-on: http://review.couchbase.org/30213
Reviewed-by: Aliaksey Kandratsenka <alkondratenko@gmail.com>
Tested-by: Aliaksey Kandratsenka <alkondratenko@gmail.com>