wpa_gui: Initialize WpaGuiApp::w in the constructor

This gets rid of a static analyzer warning. The actual value for
WpaGuiApp::w will be set after the constructor has returned, so this
value was not really used uninitialized.

Signed-off-by: Jouni Malinen <j@w1.fi>

wpa_supplicant/wpa_gui-qt4/main.cpp

@@ -19,6 +19,7 @@ WpaGuiApp::WpaGuiApp(int &argc, char **argv) :
 	argc(argc),
 	argv(argv)
 {
+	w = NULL;
 }
 
 #if !defined(QT_NO_SESSIONMANAGER) && QT_VERSION < 0x050000