Fix person migration in case of AvatarUserWrappers
Fix person migration in case of AvatarUserWrappers

some event chairpersons are actually stored as AvatarUserWrappers...

indico/indico,mvidalgarcia/indico,mic4ael/indico,ThiefMaster/indico,DirkHoffmann/indico,pferreir/indico,DirkHoffmann/indico,OmeGak/indico,indico/indico,mvidalgarcia/indico,mic4ael/indico,pferreir/indico,mvidalgarcia/indico,indico/indico,ThiefMaster/indico,ThiefMaster/indico,DirkHoffmann/indico,OmeGak/indico,OmeGak/indico,indico/indico,mvidalgarcia/indico,mic4ael/indico,mic4ael/indico,pferreir/indico,DirkHoffmann/indico,ThiefMaster/indico,OmeGak/indico,pferreir/indico