DEVEXP-672 : NullPointerException thrown when error.message is null.

Author: anu3990

lib/responder.js

@@ -1236,8 +1236,8 @@ function operationErrorListener(error) {
       return;
     }
   }
-  const errorMessage = error.message.toString();
-  if(errorMessage.includes('EPROTO') && errorMessage.includes('SSL routines') &&
+  const errorMessage = error.message ? error.message.toString(): null;
+  if(errorMessage && errorMessage.includes('EPROTO') && errorMessage.includes('SSL routines') &&
       (errorMessage.includes('wrong version number') || errorMessage.includes('WRONG_VERSION_NUMBER'))) {
     error = new Error('You have attempted to access an HTTP server using HTTPS. Please check your configuration.\n' +
         errorMessage);