Fix for randomization data returned from analytics API

  The issue this fixes is when the question is not currently set to randomization
  but was set at some time in its history.

  This is handled by now displaying an error message for this situation.
@jbau I have no problem changing the function name but I rather like the current semantics of line 1174. It seems a bit over engineered to write an additional function to set message_by_part only. Do you have a suggestion I can change the name to? Thanks.