title: Running 'ember server' causes builds to fail with an EEXIST error?
body: <p>Got this random build error while running <code>ember server</code> today. Before you ask, here are my Ember CLI, Node and NPM versions:</p>
  
  <pre><code>version: 0.1.15
  node: 0.10.33
  npm: 2.1.8
  </code></pre>
  
  <p>I created a new Ember project using <code>ember new [app name]</code>. Everything worked. I then ran <code>ember server</code>, fired up the page on <code>http://localhost:4200/</code> and the page showed. I then created a new route called index using <code>ember generate route index</code>. As always, Ember CLI created the route, the Handlebars file and a matching test.js. Immediately after this, the running Ember server process threw a build error:</p>
  
  <pre><code>file changed templates/index.hbs
  EEXIST, file already exists '/Users/Nagarjun/Code/RideBazaar/web-client/tmp/class-tmp_cache_dir-hBTLOW8N.tmp'
  Error: EEXIST, file already exists '/Users/Nagarjun/Code/RideBazaar/web-client/tmp/class-tmp_cache_dir-hBTLOW8N.tmp'
      at Object.fs.symlinkSync (fs.js:741:18)
      at symlink (/Users/Nagarjun/Code/RideBazaar/web-client/node_modules/ember-cli/node_modules/symlink-or-copy/index.js:82:14)
      at Function.symlinkOrCopySync [as sync] (/Users/Nagarjun/Code/RideBazaar/web-client/node_modules/ember-cli/node_modules/symlink-or-copy/index.js:58:5)
      at /Users/Nagarjun/Code/RideBazaar/web-client/node_modules/ember-cli/node_modules/broccoli-sourcemap-concat/node_modules/broccoli-caching-writer/index.js:103:21
      at lib$rsvp$$internal$$tryCatch (/Users/Nagarjun/Code/RideBazaar/web-client/node_modules/ember-cli/node_modules/promise-map-series/node_modules/rsvp/dist/rsvp.js:489:16)
      at lib$rsvp$$internal$$invokeCallback (/Users/Nagarjun/Code/RideBazaar/web-client/node_modules/ember-cli/node_modules/promise-map-series/node_modules/rsvp/dist/rsvp.js:501:17)
      at lib$rsvp$$internal$$publish (/Users/Nagarjun/Code/RideBazaar/web-client/node_modules/ember-cli/node_modules/promise-map-series/node_modules/rsvp/dist/rsvp.js:472:11)
      at Object.lib$rsvp$asap$$flush [as _onImmediate] (/Users/Nagarjun/Code/RideBazaar/web-client/node_modules/ember-cli/node_modules/promise-map-series/node_modules/rsvp/dist/rsvp.js:1290:9)
      at processImmediate [as _immediateCallback] (timers.js:345:15)
  </code></pre>
  
  <p>Strangely, when I hit <code>ctrl c</code>, stop the server and re-start it, the build is successful. However, when I make a change to the file again, I get the same error. Any clues?</p>