ommit unnecessary package

package.json

@@ -107,7 +107,6 @@
     "css-loader": "^0.27.1",
     "easy-livereload": "^1.2.0",
     "express-webpack-assets": "0.0.2",
-    "mkdirp": "^0.5.1",
     "mocha": "~2.2.0",
     "node-dev": "^3.1.3",
     "optimize-js-plugin": "0.0.4",