Change nullptr to NULL to compile on Ubuntu 10.04

src/main.cpp

@@ -47,7 +47,7 @@ DECLARE_CRASH_HANDLER
 int main(int argc,char *argv[])
 {
 	INSTALL_CRASH_HANDLER
-	Tango::Util *tg = nullptr;
+	Tango::Util *tg = NULL;
 	try
 	{
 		// Initialize the device server