SSL: adopted session ticket handling for OpenSSL 1.1.0.

Return 1 in the SSL_CTX_set_tlsext_ticket_key_cb() callback function
to indicate that a new session ticket is created, as per documentation.
Until 1.1.0, OpenSSL didn't make a distinction between non-negative
return values.

See https://git.openssl.org/?p=openssl.git;a=commitdiff;h=5c753de for details.

src/event/ngx_event_openssl.c

@@ -2900,7 +2900,7 @@ ngx_ssl_session_ticket_key_callback(ngx_ssl_conn_t *ssl_conn,
                      ngx_ssl_session_ticket_md(), NULL);
         ngx_memcpy(name, key[0].name, 16);
 
-        return 0;
+        return 1;
 
     } else {
         /* decrypt session ticket */