Rollback to webpack-dev-server 2.9.4

Author: lmangani

package.json

@@ -74,7 +74,7 @@
     "url-loader": "0.6.2",
     "uuid": "^3.3.2",
     "webpack": "3.8.1",
-    "webpack-dev-server": "3.1.11",
+    "webpack-dev-server": "2.9.4",
     "webpack-manifest-plugin": "1.3.2",
     "whatwg-fetch": "2.0.3"
   },