fix migration re #3973

git-svn-id: svn://develop.studip.de/studip/trunk@28471 c5b85792-5220-0410-ad23-ed5b6b8ad999
change seminar_id for moved subfolders re #3973

git-svn-id: svn://develop.studip.de/studip/trunk@28472 c5b85792-5220-0410-ad23-ed5b6b8ad999