boost 6.x-1.0-alpha4

Fix for people upgrading from previous 6.x versions of boost. Old symlinks where interfering with the creation of files.
#451630: Many log entries with boost - stale symlinks
#337364: _boost_rmdir_rf doesn't delete symlinks

See the release notes from alpha3 for more info on upgrading from previous 6.x versions of boost.
http://drupal.org/node/451224

You Must Clear The Cache After Upgrading! Cache can be cleared by going to admin/settings/performance and pressing the Clear cached data button at the bottom of the page.