Security update

This version of Webform addresses two security issues found since the 2.7 release.

- Anonymous user data may be shown to other anonymous users when the page cache is enabled.
- Unsafe markup was allowed in textfield components' prefix and suffix values.

Changes since DRUPAL-6--1-8:

Changes since DRUPAL-5--4-8:

- Security fix.
- Rules module integration.

Update.php required: Yes

Fix for SA-CONTRIB-070

Note that Drupal 5.x is not actively supported any more, it's just a security update.