3845 Don't print empty ul when there are no recipients, parents, or claims

https://code.google.com/p/otwarchive/issues/detail?id=3845

Empty elements are bad. We don't want the associations ul around when it contains nothing. Used to be https://github.com/otwcode/otwarchive/pull/1436 and then https://github.com/otwcode/otwarchive/pull/1449, but I have managed to accidentally delete this too many times.