This has been introduced in 2.5, so when upgrading from previous versions
make sure we set a default value. Otherwise, we get a notice about it
being undefined when we try to use it (and we always try to use it!).
They now share most of the code again, this time via subclassing, and they
share some code with enrol/ldap. They have also gained some features and a few
fixes.
Eloy Lafuente (stronk7)