Draft: print: Reject enroll images that can't be matched
If the score of a print matching itself is too low to match, then reject it. It can never match and it is therefore completely useless.
Also change this into a non-fatal error, the user is free to retry the enroll step in the hope that more minutiae is found (e.g. longer swipe).
I have no idea right now whether this works, but it seems like a reasonable thing to do.