Code review comment for lp:~cr3/checkbox/sru

Sorry I didn't pick these things up yesterday, but I just got the chance to actually run the thing today and I first noticed that checkbox-sru had not been given permissions. Secondly I noticed that the checkbox-sru script doesn't define a whitelist to CHECKBOX_OPTIONS, meaning it would need to be defined on the command line. I personally think it makes more sense to encode the whitelist in the script itself, just like we do with checkbox-certification-server/client