Fixes T10806. Although browsers don't seem to care about this, it's more correct to support it, and the new test console uses normal cURL and does care.

• Hit the error case for providing a chain but no key/cert.
• Used openssl s_client -connect localhost:22280 to connect to local Aphlict servers.
• With SSL but no chain, saw openssl fail to verify the remote.
• With SSL and a chain, saw openssl verify the identify of the remote.