Bad variable passed to watchdog() call

The code that logs problems with purge requests when the proxy servers block has a bug with the watchdog() call when passing the arguments for the pattern %blocking_server. Patches attached for d6 and d7.

    // Report on proxy servers that block the purge requests.
    if (!empty($purge_blocking)) {
      foreach ($purge_blocking as $purge_blocking_server) {
        watchdog(
          'purge',
          'The proxy server host %blocking_server is blocking purge requests. Please review the proxy configuration.',
          array('%blocking_server' => $purge_blocking),
          $severity = WATCHDOG_ERROR
        );
      }
    }
  }