warn when prefs.db corrupt and catch another case
warn when prefs.db corrupt and catch another case

socialpercon/anki-1,Stvad/anki,ospalh/libanki3,sunclx/anki,hssm/anki,kenjhim/anki,hssm/anki,holycrepe/anki,xuewenfei/anki,LucasCabello/anki,go38/anki,eduOS/anki,jakesyl/ruby-card,jakesyl/ruby-card,jkitching/anki,weihautin/anki,florianjacob/anki,weihautin/anki,Arthaey/anki,abeyer/anki,subfusc/anki