AM demod: fixed destructor

plugins/channelrx/demodam/amdemod.cpp

@@ -68,6 +68,9 @@ AMDemod::~AMDemod()
 {
 	DSPEngine::instance()->removeAudioSink(&m_audioFifo);
     delete m_udpBufferAudio;
+    m_deviceAPI->removeThreadedSink(m_threadedChannelizer);
+    delete m_threadedChannelizer;
+    delete m_channelizer;
 }
 
 void AMDemod::feed(const SampleVector::const_iterator& begin, const SampleVector::const_iterator& end, bool firstOfBurst __attribute__((unused)))

plugins/channelrx/demodam/amdemodplugin.cpp

@@ -7,7 +7,7 @@
 
 const PluginDescriptor AMDemodPlugin::m_pluginDescriptor = {
 	QString("AM Demodulator"),
-	QString("3.7.3"),
+	QString("3.7.4"),
 	QString("(c) Edouard Griffiths, F4EXB"),
 	QString("https://github.com/f4exb/sdrangel"),
 	true,