note model with wrong tag handle, gracefully continue


git-svn-id: svn+ssh://svn.code.sf.net/p/gramps/code/trunk@20959 4ae1f11a-8b86-4847-b8af-ab372f36d1fd
support for upgrade of database on python3


git-svn-id: svn+ssh://svn.code.sf.net/p/gramps/code/trunk@20961 4ae1f11a-8b86-4847-b8af-ab372f36d1fd