fix(export_csv): rename export to csv label

public/app/plugins/panel/graph/module.ts

@@ -125,8 +125,8 @@ class GraphCtrl extends MetricsPanelCtrl {
 
   getExtendedMenu() {
     var menu = super.getExtendedMenu();
-    menu.push({text: 'Export CSV', click: 'ctrl.exportCsv()'});
-    menu.push({text: 'Export CSV (series2columns)', click: 'ctrl.exportCsvColumns()'});
+    menu.push({text: 'Export CSV (series as rows)', click: 'ctrl.exportCsv()'});
+    menu.push({text: 'Export CSV (series as columns)', click: 'ctrl.exportCsvColumns()'});
     menu.push({text: 'Toggle legend', click: 'ctrl.toggleLegend()'});
     return menu;
   }