Fix review comments.

Signed-off-by: alex-z <blackslayer4@gmail.com>

src/gui/accountstate.cpp

@@ -571,7 +571,7 @@ void AccountState::slotCheckServerAvailibility()
             qCInfo(lcAccountState) << "Server is now available for account" << _account->davUser();
             _lastCheckConnectionTimer.invalidate();
             resetRetryCount();
-            QMetaObject::invokeMethod(this, "slotCheckConnection", Qt::QueuedConnection);
+            QMetaObject::invokeMethod(this, &AccountState::slotCheckConnection, Qt::QueuedConnection);
         }
     });
 }