Support for Boost_mobile

Hi,

I've noticed that Boost only unlink files from normal cache directory. I've enabled the Boost_mobile module, but on call boost_expire_cache() the mobile files are stayed.
I've extended the boost module boost_expire_cache() function to support boost_mobile. My Boost module is already support GZIP, this is available also in my code-snippet.

if ($filename && file_exists($filename)) {
        if (module_exists('boost_mobile')) {
          $normal_dir = boost_get_normal_cache_dir();
          $mobile_dir = boost_mobile_get_mobile_cache_dir();
          $mobile_filename = str_replace($normal_dir, $mobile_dir, $filename);
        }
        if (BOOST_GZIP && file_exists($filename.'.gz')) {
          unlink($filename.'.gz');
          if (isset($mobile_filename) && file_exists($mobile_filename)) {
            unlink($mobile_filename.'.gz');
          }
        }
        if (unlink($filename)) {
          $extra = '';
          if (isset($mobile_filename) && unlink($mobile_filename)) {
            $extra = ' (From mobile also)';
          }
          boost_log('Removed !file from the boost cache.' . $extra, array('!file' => $filename), WATCHDOG_DEBUG);
        }
        else {
          boost_log('Could not delete !file from the boost cache. Check file permissions.', array('!file' => $filename), WATCHDOG_WARNING);
        }
      }

I hope it helps somebody.