ssl-params: slow startup (patch for consideration)

[A. Schulze]

Joseph Tam:

> A. Schulze writes:
>
>> precomputing ssl-params is also possible without patching but it's a
>> little bit tricky
>> ...
>> Long version in german: https://andreasschulze.de/dovecot/ssl-params
>
> Nice.
>
> (You should probably point out to ensure ssl_parameters_regenerate is
> zero, otherwise all this work will get wiped out!)
as I read the current source ssl_parameters_regenerate is not used anymore

At least in 2.2.1[5...9] ssl_parameters_regenerate *has no effect anymore*
For that reason I developed this workaround.

Andreas