to use the old pager one can now simply override the ``getDatagridBuilder`` method in the admin class, and obviously one could also inject the pager into there, so that one does not have to create it manually (should this be a default feature? furthermore should ``\Sonata\AdminBundle\Builder\DatagridBuilderInterface`` have a ``setPager()`` method?):
```
    /**
     * @return \Sonata\AdminBundle\Builder\DatagridBuilderInterface
     */
    public function getDatagridBuilder()
    {
        $this->datagridBuilder->setPager(new Pager());
        return $this->datagridBuilder;
    }
```

/cc @rande @sjopet