openssl: LibreSSL and BoringSSL do not use TLS_client_method

Although OpenSSL 1.1.0+ deprecated SSLv23_client_method in favor of
TLS_client_method LibreSSL and BoringSSL didn't and still use
SSLv23_client_method.

Bug: https://github.com/bagder/curl/commit/49a6642#commitcomment-11578009


Reported-by:  <asavah@users.noreply.github.com>