Fixes richardgirges#256. Unpipe busboy after error and skip further stream processing.

Author: PawelSuwinski

lib/processMultipart.js

@@ -60,7 +60,8 @@ module.exports = (options, req, res, next) => {
 
     const writePromise = options.useTempFiles
       ? getWritePromise().catch(err => {
-        uploadTimer.clear();
+        req.unpipe(busboy);
+        req.resume();
         cleanup();
         next(err);
       }) : getWritePromise();