fixed calling QApplication constructor with temp ref

mix/MixApplication.cpp

@@ -33,7 +33,7 @@
 
 using namespace dev::mix;
 
-MixApplication::MixApplication(int _argc, char* _argv[]):
+MixApplication::MixApplication(int& _argc, char* _argv[]):
 	QApplication(_argc, _argv), m_engine(new QQmlApplicationEngine()), m_appContext(new AppContext(m_engine.get()))
 {
 	setOrganizationName(tr("Ethereum"));

mix/MixApplication.h

@@ -40,7 +40,7 @@ class MixApplication: public QApplication
 	Q_OBJECT
 
 public:
-	MixApplication(int _argc, char* _argv[]);
+	MixApplication(int& _argc, char* _argv[]);
 	virtual ~MixApplication();
 	AppContext* context() { return m_appContext.get(); }
 	QQmlApplicationEngine* engine() { return m_engine.get(); }