docs/changelog: Note that we have replaced the message debug pages with logging.

git-svn-id: https://simplesamlphp.googlecode.com/svn/trunk@2545 44740490-163a-0410-bde0-09ae8108e29a

docs/simplesamlphp-changelog.txt

@@ -27,6 +27,7 @@ See the upgrade notes for specific information about upgrading.
   * Moved function from Utilities-class to more appropriate locations.
       * `getAuthority` to `SimpleSAML_IdP`
       * `generateUserId` to `sspmod_saml_IdP_SAML2`.
+  * Replaced the message debug pages with logging of sent and received messages to the log file.
   * Removed metadata send functionality from old SP code.
   * Removed bin/test.php and www/admin/test.php.
   * Removed metashare.