Jakob Petsovits commented on merge request !600 at Plasma / PowerDevil

Replaced with a direct instantiation of QDBusInterface called via QDBusConnection::systemBus().asyncCall().

I considered importing the XML interface and using the generated class instead, but it seemed overkill for one call, which would also lose its asynchronity. (Other uses of login1 require signals or overloading with ConsoleKit, so there's no apparent benefit to switching these over either.)