use tls.CertificateVerificationError instead of redefining it

Author: marten-seemann

common.go

@@ -1451,16 +1451,4 @@ func isSupportedSignatureAlgorithm(sigAlg SignatureScheme, supportedSignatureAlg
 }
 
 // CertificateVerificationError is returned when certificate verification fails during the handshake.
-type CertificateVerificationError struct {
-	// UnverifiedCertificates and its contents should not be modified.
-	UnverifiedCertificates []*x509.Certificate
-	Err                    error
-}
-
-func (e *CertificateVerificationError) Error() string {
-	return fmt.Sprintf("tls: failed to verify certificate: %s", e.Err)
-}
-
-func (e *CertificateVerificationError) Unwrap() error {
-	return e.Err
-}
+type CertificateVerificationError = tls.CertificateVerificationError