Remove redundant initialization

Source/Core/AudioCommon/PulseAudioStream.cpp

@@ -15,9 +15,7 @@ namespace
 const size_t BUFFER_SAMPLES = 512;  // ~10 ms - needs to be at least 240 for surround
 }
 
-PulseAudio::PulseAudio() : m_thread(), m_run_thread()
-{
-}
+PulseAudio::PulseAudio() = default;
 
 bool PulseAudio::Init()
 {