Log Message:
Update drupal6 package to 6.4.

Drupal 6.4, 2008-08-13
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- Fixed a security issue (Cross site scripting, Arbitrary file uploads via
  BlogAPI, Cross site request forgeries and Various Upload module
  vulnerabilities), see SA-2008-047.
- Improved error messages during installation.
- Fixed a bug that prevented AHAH handlers to be attached to radios widgets.
- Fixed a variety of small bugs.