Use static interface definition for UPower DBus interface
Instantiation of a dynamic QDbusInterface does an implicit synchronous DBus "Introspect" method call. This can be avoided by using a static, compile time interface based on QDBusAbstractInterface.
To avoid having an implementation for the long obsolete UPower 0.9 interface, the first patch removes the old interface.
UPower 0.99.0 has been relased in 2013, and all contemporary distributions have a sufficiently recent version: