provide debug info when collection corrupt
provide debug info when collection corrupt

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