PluginManager: removed useless dependency on main window

sdrbase/plugin/pluginmanager.cpp

@@ -42,8 +42,7 @@ const QString PluginManager::m_fileSinkDeviceTypeID = "sdrangel.samplesink.files
 
 PluginManager::PluginManager(MainWindow* mainWindow, QObject* parent) :
 	QObject(parent),
-	m_pluginAPI(this, mainWindow),
-	m_mainWindow(mainWindow)
+	m_pluginAPI(this, mainWindow)
 {
 }
 

sdrbase/plugin/pluginmanager.h

@@ -115,7 +115,6 @@ private:
 	typedef QList<SamplingDevice> SamplingDevices;
 
 	PluginAPI m_pluginAPI;
-	MainWindow* m_mainWindow;
 	Plugins m_plugins;
 
 	PluginAPI::ChannelRegistrations m_rxChannelRegistrations; //!< Channel plugins register here