Revert pyqt3TQtSignal to pyqt3QtSignal

It allows to retain compatibility with the original SIP4

sip/qt/qobject.sip

@@ -2196,7 +2196,7 @@ int pyqt3EmitSignal(PyObject *self, const char *sig, PyObject *sigargs)
     // See if it is a TQt signal.
     if (*sig == '2')
     {
-        pyqt3TQtSignal *tab;
+        pyqt3QtSignal *tab;
 
         // Search the table.
         for (tab = ((pyqt3ClassTypeDef *)((sipWrapperType *)(self->ob_type))->type)->qt3_emit; tab->st_name != NULL; ++tab)