Don't use deprecated RSA_generate_key.
Don't use deprecated RSA_generate_key.

Motivation:

OpenSSL has deprecated RSA_generate_key and replaced it with
RSA_generate_key_ex.

Modifications:

This change switches the code to use the new function.

Result:

This should not have a semantic difference.

RSA_generate_key was already deprecated in OpenSSL 0.9.8 so using the
new function should not break anything. Additionally, it means that the
code can drop an #ifdef that skipped this call with OpenSSL 1.1.0,
presumably because using the deprecated function was causing
compile-time issues.

netty/netty-tcnative,netty/netty-tcnative,netty/netty-tcnative,netty/netty-tcnative