[mod_openssl] use SSL_CTX_set_client_hello_cb()
[mod_openssl] use SSL_CTX_set_client_hello_cb()

use SSL_CTX_set_client_hello_cb() when available

(obsoletes SSL_CTX_set_tlsext_servername_callback()
 and SSL_CTX_set_tlsext_servername_arg())

lighttpd/lighttpd1.4,gstrauss/lighttpd1.4,gstrauss/lighttpd1.4,gstrauss/lighttpd1.4,lighttpd/lighttpd1.4,lighttpd/lighttpd1.4,lighttpd/lighttpd1.4,gstrauss/lighttpd1.4,gstrauss/lighttpd1.4,gstrauss/lighttpd1.4,lighttpd/lighttpd1.4,lighttpd/lighttpd1.4