Fixed a bug where an error in a proof verification allowed a positive…

[vdods]

… Check::Proof to be added to the verification results in addition to the expected error. This fixes it to match the analogous logic in other proof verification code.

[vdods]

This only required fixing a typo. The bug in particular was that I was seeing

VerificationResult { checks: [Proof], warnings: [], errors: [ "signature error: Verification equation was not satisfied" ] }

when I should have been seeing

VerificationResult { checks: [], warnings: [], errors: [ "signature error: Verification equation was not satisfied" ] }