Actually, I think those three lines should go into Curl_none_cleanup(). Consequently, that function should be renamed to Curl_multissl_cleanup(), and it should be moved directly after Curl_multissl_init().
When cURL is compiled with support for multiple SSL backends, it is
possible to configure an SSL backend via `curl_global_sslset()`, but
only *before* `curl_global_init()` was called.
If another SSL backend should be used after that, a user might be
tempted to call `curl_global_cleanup()` to start over. However, we did
not foresee that use case and forgot to reset the SSL backend in that
Let's allow that use case.
This addresses curl#5255
Signed-off-by: Johannes Schindelin <firstname.lastname@example.org>