Prevent persona from being linked with any other personas
This function will add a wildcard * to the set of anti-links, which will prevent the persona from being linked with any 
            other personas.
To make the persona linkable again you need to remove the global anti-link
This method is safe to call multiple times concurrently (e.g. begin one asynchronous call, then begin another before the first has finished).
| PropertyError | if setting the anti-links failed | 
0.9.7