fixed HTTP-version error detection

server_http.hpp

@@ -739,11 +739,16 @@ namespace SimpleWeb {
                 return;
               }
             }
+	    try{
             if(std::stof(response->session->request->http_version) >= 1.1) {
               auto new_session = std::make_shared<Session>(this->config.max_request_streambuf_size, response->session->connection);
               this->read(new_session);
               return;
             }
+          }
+	    catch(std::exception &){
+	      return;
+	    }
 	  }
           else if(this->on_error)
             this->on_error(response->session->request, ec);