Once we use DNS -> A record resolution for round robin DNS, we need customize the TLS certificate validation to validate certificates against something other then a certificate.

Steps:

1. Create a synchronous TCP connection by using Socket in src/mongo/util/net/sock.h
2. Call Socket::connect()
3. Call ldap_init_fd with the DNS name of the server we are connecting to instead of the IP address we connected with.
4. Call ldap_install_tls if TLS

See https://pagure.io/SSSD/sssd/issue/905 for details.