paypro: fix browser kjur usage.

lib/browser/PayPro.js

@@ -119,7 +119,7 @@ PayPro.prototype.x509Verify = function(key) {
     // Create a To-Be-Signed Certificate to verify using asn1.js:
     // Fails at Issuer:
     var tbs = rfc3280.TBSCertificate.encode(c.tbsCertificate, 'der');
-    jsrsaSig.updateHex(tbs);
+    jsrsaSig.updateHex(tbs.toString('hex'));
 
     return jsrsaSig.verify(sig);
   });