Remove direct path to mocha binary

package.json

@@ -4,7 +4,7 @@
   "description": "Datadog API Node.JS Client",
   "main": "lib/index.js",
   "scripts": {
-    "test": "./node_modules/.bin/mocha --recursive ./test",
+    "test": "mocha --recursive ./test",
     "docs": "node ./docs/create.js > index.html"
   },
   "bin": {