adaption for python version less 3.x (see issue 6465) for details

git-svn-id: svn+ssh://svn.code.sf.net/p/gramps/code/trunk@21516 4ae1f11a-8b86-4847-b8af-ab372f36d1fd
Better translation for compare events.

git-svn-id: svn+ssh://svn.code.sf.net/p/gramps/code/trunk@21518 4ae1f11a-8b86-4847-b8af-ab372f36d1fd