Don't return existing session id when the wrong one is supplied

src/server.rs

@@ -105,9 +105,8 @@ impl<T: WebDriverHandler<U>, U: WebDriverExtensionRoute> Dispatcher<T, U> {
                         if existing_session.id != *msg_session_id {
                             Err(WebDriverError::new(
                                 ErrorStatus::InvalidSessionId,
-                                format!("Got unexpected session id {} expected {}",
-                                        msg_session_id,
-                                        existing_session.id)))
+                                format!("Got unexpected session id {}",
+                                        msg_session_id)))
                         } else {
                             Ok(())
                         }