Update apahce22 package to 2.2.21.

Quote from release announce:

  The Apache Software Foundation and the Apache HTTP Server Project are
  pleased to announce the release of version 2.2.21 of the Apache HTTP
  Server ("Apache").  This version of Apache is principally a security
  and bug fix release:

    * SECURITY: CVE-2011-3348 (cve.mitre.org)
      mod_proxy_ajp when combined with mod_proxy_balancer: Prevents
      unrecognized HTTP methods from marking ajp: balancer members
      in an error state, avoiding denial of service.

    * SECURITY: CVE-2011-3192 (cve.mitre.org)
      core: Further fixes to the handling of byte-range requests to use
      less memory, to avoid denial of service. This patch includes fixes
      to the patch introduced in release 2.2.20 for protocol compliance,
      as well as the MaxRanges directive.

  Note the further advisories on the state of CVE-2011-3192 will no longer
  be broadcast, but will be kept up to date at;

    http://httpd.apache.org/security/CVE-2011-3192.txt

  We consider this release to be the best version of Apache available, and
  encourage users of all prior versions to upgrade.

(taca)