fix capthca

@@ -87,11 +87,9 @@ const generateQiniu = (req, res, next) => {
         req.session.captcha = result.data.text;
         req.session.captchaCount = 0;
 
-        let imageUrl = result.data.images + `/watermark/2/text/${uuid.v4()}/fontsize/120/dissolve/10`;
-
         res.type('png');
         if (result.code === 200) {
-            request(imageUrl).pipe(res);
+            request(result.data.images).pipe(res);
         }
 
     }).catch(next);

@@ -5,6 +5,7 @@
 'use strict';
 
 const api = require('./captcha-api');
+const uuid = require('uuid');
 
 exports.generateCaptcha = () => {
     return api.gen().then((result) => {
@@ -17,7 +18,8 @@ exports.generateCaptcha = () => {
                 code: 200,
                 data: {
                     text: codeStr,
-                    images: `${result.data.verifiedGraphicCode}?imageView/2/w/240`
+                    images: `${result.data.verifiedGraphicCode}` +
+                            `?imageView/2/w/240/watermark/2/text/${uuid.v4()}/fontsize/120/dissolve/10`
                 }
             };
         } else {