Fix logout not working when server offline

src/client/action/logout.js

@@ -1,13 +1,16 @@
 import initMatrix from '../initMatrix';
 
-function logout() {
+async function logout() {
   const mx = initMatrix.matrixClient;
   mx.stopClient();
-  mx.logout().then(() => {
+  try {
+    await mx.logout();
+  } catch {
+    // ignore if failed to logout
+  }
   mx.clearStores();
   window.localStorage.clear();
   window.location.reload();
-  });
 }
 
 export default logout;