Remove weird import

public/app/features/dashboard/dashboard_model.ts

@@ -9,7 +9,6 @@ import sortByKeys from 'app/core/utils/sort_by_keys';
 
 import { PanelModel } from './panel_model';
 import { DashboardMigrator } from './dashboard_migration';
-import { tickStep } from '../../core/utils/ticks';
 
 export class DashboardModel {
   id: any;