[N1QL RBAC]User with query_select role on a bucket able to insert values into another bucket

1. create a bucket default with no documents.
2. Add beer-sample bucket.
3. create a user test with password as <<password>> with role as query_select on beer-sample through UI.
4. Try the following query through cbq:
cbq> [root@localhost bin]# ./cbq -u test -p password
Connected to : http://localhost:8091/. Type Ctrl-D or \QUIT to exit.

Path to history file for the shell : /root/.cbq_history
cbq> INSERT INTO default (KEY UUID(), VALUE name) select name from `beer-sample` ;
{
"requestID": "5e58bf18-2fae-40b1-9223-dba72cb66069",
"signature": null,
"results": [
],
"status": "success",
"metrics":

{ "elapsedTime": "7.227159727s", "executionTime": "7.227109025s", "resultCount": 0, "resultSize": 0, "mutationCount": 7303 }

}

User test should not be allowed to insert docs in default.