create_ssl_context: Don't skip ctx.load_cert_chain calls

[scollinson]

…s a str

Summary

create_ssl_context returns early when verify is a str, bypassing calls to ctx.load_cert_chain to load the client certificates.

Checklist

• [x] I understand that this PR may be closed in case there was no previous discussion. (This doesn't apply to typos!)
• [ ] I've added a test for each change that was introduced, and I tried as much as possible to make a single atomic change.
• [ ] I've updated the documentation accordingly.