Fix s3 path jshint error

Author: twaggs

lib/s3.js

@@ -5,7 +5,6 @@ var AWS        = require('aws-sdk');
 var CoreObject = require('core-object');
 var Promise    = require('ember-cli/lib/ext/promise');
 var fs         = require('fs');
-var path       = require('path');
 var readFile   = Promise.denodeify(fs.readFile);
 var mime       = require('mime-types');