bug fix: none instead of pdf to graph_format

matlab/dyn_saveas.m

@@ -54,6 +54,10 @@ if any(strcmp('fig',cellstr(DynareOptions.graph_format)))
         saveas(h,[fname '.fig']);
     end
 end
+if any(strcmp('none',cellstr(DynareOptions.graph_format)))
+% don't save
+% check here as a reminder that none is an option to graph_format
+end
 if DynareOptions.nodisplay
     close(h);
 end

preprocessor/DynareBison.yy

@@ -2262,7 +2262,7 @@ allowed_graph_formats : EPS
                       | PDF
                         { driver.add_graph_format("pdf"); }
                       | NONE
-                        { driver.add_graph_format("pdf"); }
+                        { driver.add_graph_format("none"); }
                       ;
 list_allowed_graph_formats : allowed_graph_formats
                            | list_allowed_graph_formats COMMA allowed_graph_formats