title: RequireJS loading issue (with packages)
body: <p>I am using RequireJS 2.0.6. And sometimes I have a laoding issue with one of my library (amplifyjs).</p>
  
  <p>Project:</p>
  
  <pre><code>libs/
      amplify.js
      handlebars.js
      jquery.js
      require.js
  packages/
      core/
          main.js
  index.html
  main.js
  </code></pre>
  
  <p>My main.js:</p>
  
  <pre><code>require.config({
      paths: {
          'jquery': '../libs/jquery',
          'amplify': '../libs/amplify',
          'handlebars': '../libs/handlebars'
      },
      shim: {
          'jquery': {
              exports: '$'
          },
          'amplify': {
              deps: ['jquery'],
              exports: 'amplify'
          },
          'handlebars': {
              exports: 'handlebars'
          }
      },
      packages: ['core'],
      baseUrl: './packages/'
  });
  
  require(['jquery', 'amplify', 'handlebars', 'core'], function() {
  });
  </code></pre>
  
  <p>Index.html:</p>
  
  <pre><code>&lt;script type="text/javascript" data-main="main" src="libs/require.js"&gt;&lt;/script&gt;
  </code></pre>
  
  <p>75% of time it works but sometimes I get this error:</p>
  
  <pre><code>GET http://localhost:8888/aa/test/packages/libs/amplify.js 404 (Not Found) 
  Uncaught Error: Script error
      http://requirejs.org/docs/errors.html#scripterror 
  </code></pre>
  
  <p>The path is wrong! But I cannot figure out why this happens ? And why only sometimes ?</p>
  
  <p>(I am pretty sure it has to do something with the package, but I have no idea why it does that)</p>