[lipstick] Fix unit tests

This makes all the tests pass for me.
Ah, remembered wrong. The connect still worked, but running the devicelock test printed out a lot of warnings like this:

QWARN  : Ut_DeviceLock::testInitialState() [W] err_method_notfound:2153 - QObject::connect: No such signal QGuiApplication::homeReady() in ../../src/devicelock/devicelock.cpp:72