small update in formHeaders for body encoding type multipart/form-data

lib/util.js

@@ -825,6 +825,7 @@ module.exports = {
               if (encoding[key].headers[key].hasOwnProperty('$ref')) {
                 encoding[key].headers[key] = getRefObject(encoding[key].headers[key].$ref);
               }
+              encoding[key].headers[key].name = key;
               formHeaders.push(this.convertToPmHeader(encoding[key].headers[key]));
             }
           });