I haven't found anything to work outside of "erase all content and settings" or restoring the phone via itunes 🙁
One thing that seemed to prevent it from happening in the first place though is to monitor when your phone is downloading the update via settings > general > usage and if it has started downloading but hasn't finished yet, delete the update before it finishes downloading completely and you won't have a badge on the settings app.
It is annoying to look at though.