mod_throttle is added to the default server since Jan 10 but there is no
commented LoadModule/AddModule as there is with the other "added" modules
mod_define has no LoadModule/AddModule pair on httpd.conf either.
mod_define is not explicitally included (as mod_throttle) but implicitally
as a mod_ssl EAPI extension
I'd rather avoid modifying the default configuration file until a major release
(to minimize unexpected things happening when users have modified theirs), so
I'm going to resolve this as 'deferred'.
We're adding a default ssl session cache, so I'll go ahead and make this change.