...after 54f10a96 "tdf#93404: Forgot to launch
WakeUpThread," when the WakeUpThread blocks on locking
StatusIndicatorFactory::m_mutex in StatusIndicatorFactory::update() while the
joining thread blocks on StatusIndicatorFactory::impl_stopWakeUpThread() ->
WakeUpThread::stop() -> Thread::join().

Change-Id: I3480014b1f522901064ea9b71ffa2ebf5d74fef5