Remove custom migration exception
Remove custom migration exception

This was hiding the true error message from ever hitting logs.
Made to help disagnose #2711.

EVAST9919/osu,2yangk23/osu,UselessToucan/osu,johnneijzen/osu,smoogipooo/osu,smoogipoo/osu,UselessToucan/osu,johnneijzen/osu,peppy/osu-new,peppy/osu,UselessToucan/osu,NeoAdonis/osu,naoey/osu,EVAST9919/osu,naoey/osu,ppy/osu,DrabWeb/osu,ZLima12/osu,ZLima12/osu,NeoAdonis/osu,peppy/osu,NeoAdonis/osu,2yangk23/osu,naoey/osu,ppy/osu,DrabWeb/osu,ppy/osu,smoogipoo/osu,smoogipoo/osu,peppy/osu,DrabWeb/osu