Add cass_ssl_set_default_verify_paths API

[m8mble]

Forwards SSL-configuration to use system default directories for finding certificate authorities.

Similar functionality is often desired / provided by similar SSL-context forwarding APIs, e.g. boost ssl context.

[mpenick]

Sorry for the delay. Thanks for the PR. Looks great, very thorough.

Calling SSL_CTX_set_default_verify_paths() as default internally would be a bad idea because it might add CAs the application does not intend?

Would you be able to add a unit test for this? (Looks like it might be possible to control the default paths with env. variables e.g. SSL_CERT_DIR)

[m8mble]

Thanks for your feedback.

I don't think SSL_CTX_set_default_verify_paths by default would be a good idea: For one, it would simply be a breaking change. And for two, it's probably preferable to stay as close as possible to the actual openssl API.

I've added a basic unit test to demonstrate the intended behavior. Thanks for the environment variable hint: I used SSL_CERT_FILE which should be simpler to use platform independently.

Happy easter, everyone!

[m8mble]

I regret having mentioned platform independence ;).

Unfortunately, I don't have a windows box at hand to reproduce. But I'll try my best to make things work using your CI...

[m8mble]

Ok, at this point I could use some help. Whats so special about the VS12 pipeline, that makes it succeed while all others fail? Any ideas?

[mpenick]

Thanks for the test and trying to make it work on all platforms. I'll take a look.

[mpenick]

I worked on this a bit yesterday on my local Windows machine. I thought I found the issue, and I'm able to get it working locally, but when I push it only one out of six CI builds works. I'll have to dig into this more.

[mpenick]

Note: It works locally with many different versions of VS.