remove SESSION_NAME from env.dev.js

config/env.dev.js

@@ -1,7 +1,6 @@
 module.exports = {
   NODE_ENV: 'development',
   FILE_UPLOAD: 'local',
-  SESSION_NAME: 'connect.growi-dev.sid',
   // MATHJAX: 1,
   ELASTICSEARCH_URI: 'http://localhost:9200/growi',
   HACKMD_URI: 'http://localhost:3010',