Some clicks on Random give an Internal Server Error

Message in the log is:

```
   File "/usr/local/apache2/htdocs/dynamic/searchmysite/search/search.py", line 127, in random
     domain_name = response['grouped']['domain']['groups'][0]['groupValue']
                  ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~^^^
 IndexError: list index out of range
```

Not sure what domain(s) are triggering this, so will need to investigate further.
