Today, if the server starts and finds itself using OpenSSL 1.1.1 or newer, and the standard libldap library, it will warn:

"OpenSSL 1.1.1 and higher has no performance impact "
"with libldap_r. Link mongod against libldap_r to enable "
"concurrent use of LDAP. "
"Your OpenSSL version is: " OPENSSL_VERSION_TEXT

The server will also disable its use of the multithreaded LDAP connection pool.

We should remove this behavior because:

• Switching from libldap to libldap_r is very hard. We should not ask the user to do so without a very good reason.
• Running without the connection pool by default is a poor experience.
• We do not have evidence of reliability concerns with libldap when used in conjunction with OpenSSL 1.1.1