title: hook_schema() not getting uninstalled when module is disabled
body: <p>I have installed a schema for a custom module which creates the table when I enable the module. But when I disable the module, the table still remains. I am using the following code for uninstall:</p>
  
  <pre class="lang-php prettyprint-override"><code>function sample2_install() {
    if(!db_table_exists('contact')){
      drupal_install_schema('sample2');
    }
  }
  
  function sample2_uninstall() {
    drupal_uninstall_schema('sample2');
  }
  </code></pre>
  
  <p>Why is the table not getting uninstalled?</p>