nghttpx: Fix crash with plain text HTTP

src/shrpx_http2_downstream_connection.cc

@@ -340,7 +340,7 @@ int Http2DownstreamConnection::push_request_headers() {
 #if OPENSSL_1_1_1_API
   auto conn = handler->get_connection();
 
-  if (!SSL_is_init_finished(conn->tls.ssl)) {
+  if (conn->tls.ssl && !SSL_is_init_finished(conn->tls.ssl)) {
     nva.push_back(http2::make_nv_ll("early-data", "1"));
   }
 #endif // OPENSSL_1_1_1_API

src/shrpx_http_downstream_connection.cc

@@ -590,7 +590,7 @@ int HttpDownstreamConnection::push_request_headers() {
 #if OPENSSL_1_1_1_API
   auto conn = handler->get_connection();
 
-  if (!SSL_is_init_finished(conn->tls.ssl)) {
+  if (conn->tls.ssl && !SSL_is_init_finished(conn->tls.ssl)) {
     buf->append("Early-Data: 1\r\n");
   }
 #endif // OPENSSL_1_1_1_API