MB-19339: Simplify RBAC check for stats
MB-19339: Simplify RBAC check for stats

Change-Id: I36bec12b9da6f1f220859f55bd648ae5324712f1
Reviewed-on: http://review.couchbase.org/74244
Tested-by: Build Bot <80754af91bfb6d1073585b046fe0a474ce868509@couchbase.com>
Reviewed-by: Jim Walker <1cd02e31b43620d7c664e038ca42a060d61727b9@couchbase.com>

couchbase/memcached,daverigby/kv_engine,daverigby/kv_engine,daverigby/memcached,daverigby/memcached,daverigby/memcached,daverigby/kv_engine,daverigby/kv_engine,couchbase/memcached,couchbase/memcached,daverigby/memcached,couchbase/memcached