Anonymous sparql update with default shiro.ini

After creating a dataset `ds` I have following endpoints
```
SPARQL Query:    /ds/ 
SPARQL Query:    /ds/query 
SPARQL Query:    /ds/sparql 
SPARQL Update:    /ds/ 
SPARQL Update:    /ds/update 
```
Authentication is only required for `/ds/update` but not for `/ds`.