Fix FTBFS with GCC6

Signed-off-by: Slávek Banko <slavek.banko@axis.cz>

src/kqalculate.cpp

@@ -5728,7 +5728,7 @@ void KQalculate::newMatrix() {
 
 void KQalculate::newVariable() {
 	if(!variable_edit_dialog) {
-		variable_edit_dialog = new QalculateEditVariableDialog(false);
+		variable_edit_dialog = new QalculateEditVariableDialog(0);
 	}
 	Variable *v = variable_edit_dialog->editVariable(i18n("My Variables"));
 	if(v) {