title: Can't override extended twig template block to empty
body: <p>I'm using <em>MopaBootstrapBundle</em> in <em>Symfony 2.1.3</em> with <em>Twig</em> templates.
  This bundle has <em>base.html.twig</em> template which contains scripts block:</p>
  
  <pre><code>{% block foot_script %}
      {# To only use a subset or add more js overwrite and copy paste this block
      To speed up page loads save a copy of jQuery in your project and override this block to include the correct path
      Otherwise the regeneration is done on every load in dev more with use_controller: true
       #}
      {% javascripts
          'http://ajax.googleapis.com/ajax/libs/jquery/1.7.1/jquery.min.js'
          '@MopaBootstrapBundle/Resources/bootstrap/js/bootstrap-transition.js'
          '@MopaBootstrapBundle/Resources/bootstrap/js/bootstrap-modal.js'
          '@MopaBootstrapBundle/Resources/bootstrap/js/bootstrap-dropdown.js'
          '@MopaBootstrapBundle/Resources/bootstrap/js/bootstrap-scrollspy.js'
          '@MopaBootstrapBundle/Resources/bootstrap/js/bootstrap-tab.js'
          '@MopaBootstrapBundle/Resources/bootstrap/js/bootstrap-tooltip.js'
          '@MopaBootstrapBundle/Resources/bootstrap/js/bootstrap-popover.js'
          '@MopaBootstrapBundle/Resources/bootstrap/js/bootstrap-alert.js'
          '@MopaBootstrapBundle/Resources/bootstrap/js/bootstrap-button.js'
          '@MopaBootstrapBundle/Resources/bootstrap/js/bootstrap-collapse.js'
          '@MopaBootstrapBundle/Resources/bootstrap/js/bootstrap-carousel.js'
          '@MopaBootstrapBundle/Resources/bootstrap/js/bootstrap-typeahead.js'
          '@MopaBootstrapBundle/Resources/public/js/mopabootstrap-collection.js'
          '@MopaBootstrapBundle/Resources/public/js/mopabootstrap-subnav.js'
      %}
  &lt;script type="text/javascript" src="{{ asset_url }}"&gt;&lt;/script&gt;
  {% endjavascripts %}
  {% endblock foot_script %}
  </code></pre>
  
  <p>I'm extending it in my template using:</p>
  
  <pre><code>{% extends 'MopaBootstrapBundle::base.html.twig' %}
  {% block foot_script %}{% endblock foot_script %}
  </code></pre>
  
  <p>But it still tries to load Bundle's <em>base.html.twig</em> template and I get:</p>
  
  <blockquote>
    <p>An exception has been thrown during the compilation of a template
    ("Unable to find file
    "@MopaBootstrapBundle/Resources/bootstrap/js/bootstrap-transition.js".")
    in "MopaBootstrapBundle::base.html.twig".</p>
  </blockquote>
  
  <hr>
  
  <p>What I've found out is, that if you extend it like this:</p>
  
  <pre><code>{% extends 'MopaBootstrapBundle::base.html.twig' %}
  {% block foot_script %}
      {% javascripts
          '@MopaBootstrapBundle/Resources/bootstrap/js/bootstrap-typeahead.js'
          '@MopaBootstrapBundle/Resources/public/js/mopabootstrap-collection.js'
          '@MopaBootstrapBundle/Resources/public/js/mopabootstrap-subnav.js'
      %}
  &lt;script type="text/javascript" src="{{ asset_url }}"&gt;&lt;/script&gt;
  {% endjavascripts %}
  {% endblock foot_script %}
  </code></pre>
  
  <p>Note the <em>typeahead.js</em></p>
  
  <p>I get:</p>
  
  <blockquote>
    <p>An exception has been thrown during the compilation of a template
    ("Unable to find file
    "@MopaBootstrapBundle/Resources/bootstrap/js/bootstrap-typeahead.js".")
    in "MopaBootstrapBundle::base.html.twig".</p>
  </blockquote>
  
  <p>If I remove just one line:</p>
  
  <pre><code>{% extends 'MopaBootstrapBundle::base.html.twig' %}
  {% block foot_script %}
      {% javascripts
          '@MopaBootstrapBundle/Resources/public/js/mopabootstrap-collection.js'
          '@MopaBootstrapBundle/Resources/public/js/mopabootstrap-subnav.js'
      %}
  &lt;script type="text/javascript" src="{{ asset_url }}"&gt;&lt;/script&gt;
  {% endjavascripts %}
  {% endblock foot_script %}
  </code></pre>
  
  <p>I get:</p>
  
  <blockquote>
    <p>An exception has been thrown during the compilation of a template
    ("Unable to find file
    "@MopaBootstrapBundle/Resources/bootstrap/js/bootstrap-transition.js".")
    in "MopaBootstrapBundle::base.html.twig".</p>
  </blockquote>
  
  <p>It still tries to load all the scripst from base template.</p>
  
  <p>Any suggestions how to override *foot_script* block to make it empty and not to load these JS files?</p>