build fix

Author: Alain Dumesny

package.json

@@ -8,7 +8,7 @@
     "url": "git+https://github.com/gridstack/gridstack.js.git"
   },
   "scripts": {
-    "build": "rm dist/* && grunt && doctoc ./README.md && doctoc ./doc/README.md && doctoc ./doc/CHANGES.md",
+    "build": "grunt && doctoc ./README.md && doctoc ./doc/README.md && doctoc ./doc/CHANGES.md",
     "test": "grunt lint && karma start karma.conf.js",
     "lint": "grunt lint",
     "reset": "rm -rf dist node_modules",