Symfony 1 relocate cache dir for vagrant use

ProjectConfiguration.php

<?php

require_once dirname(__FILE__).'/../lib/vendor/symfony/lib/autoload/sfCoreAutoload.class.php';
sfCoreAutoload::register();

class ProjectConfiguration extends sfProjectConfiguration
{
  public function setup()
  {
    $this->enablePlugins('sfDoctrinePlugin');
    $this->enablePlugins('sfDoctrineGuardPlugin');
    $this->enablePlugins('mpRealityAdminPlugin');
    $this->enablePlugins('sfFormExtraPlugin');


    //sfWidgetFormSchema::setDefaultFormFormatterName('ac2009');    
    $this->enablePlugins('sfPhpExcelPlugin');
    $this->enablePlugins('sfPHPUnit2Plugin');
  }

  public function configureDoctrine(Doctrine_Manager $manager)
  {
    $manager->registerHydrator('at_scalar_array', 'AtDoctrineHydratorScalarArray');
    $manager->registerHydrator('at_pair_array', 'AtDoctrineHydratorPairArray');
  }

  public function setRootDir($rootDir)
  {
    parent::setRootDir($rootDir);
    $this->setCacheDir('/dev/shm/dreyfussf1/');
  }
}