MINOR: ssl: Remove call to SSL_CTX_set_tlsext_ticket_key_cb with OpenSSLv3

MINOR: ssl: Remove call to SSL_CTX_set_tlsext_ticket_key_cb with OpenSSLv3

SSL_CTX_set_tlsext_ticket_key_cb was deprecated on OpenSSLv3 because it
uses an HMAC_pointer which is deprecated as well. According to the v3's
manpage it should be replaced by SSL_CTX_set_tlsext_ticket_key_evp_cb
which uses a EVP_MAC_CTX pointer.
This new callback was introduced in OpenSSLv3 so we need to keep the two
calls in the source base and to split the usage depending on the OpenSSL
version.