修复下载链接问题

api/channel_build.py

@@ -52,7 +52,7 @@ class ChannelList(APIView):
             error_logger.error(u'获取渠道列表失败：%s', e)
             raise e
         data = {'total': channel_list.get('total', 0)}
-        url = settings.APK_DOMAIN + settings.APK_RELEASE_DIR + "/{name}/gm_alpha_{name}.apk"
+        url = settings.APK_DOMAIN + settings.APK_BUILD_DIR + '/' + settings.APK_RELEASE_DIR + "/{name}/gm_alpha_{name}.apk"
         channels = [
             {
                 'id': data.get('id'),