fix 微信SDK异步加载 造成Crash

www/webapp/common/js/config.js

@@ -29,6 +29,7 @@ define(function (require) {
   if (ua.match(/MicroMessenger/i) == 'micromessenger') {
     isWX = true;
     require(['http://res.wx.qq.com/open/js/jweixin-1.0.0.js'], function(wx) {
+      if (typeof wx === 'undefined') return;
       var wxSignObject = document.getElementById('wxMain');
       if (wxSignObject) {
         var wxConfig = JSON.parse(wxSignObject.getAttribute('data-sign'));