fix for panel-initialized event not being called

(cherry picked from commit 757cada4a5)

public/app/features/dashboard/dashboard_model.ts

@@ -223,6 +223,8 @@ export class DashboardModel {
   }
 
   panelInitialized(panel: PanelModel) {
+    panel.initialized();
+
     if (!this.otherPanelInFullscreen(panel)) {
       panel.refresh();
     }

public/app/features/dashboard/panel_model.ts

@@ -132,7 +132,7 @@ export class PanelModel {
     }
   }
 
-  panelInitialized() {
+  initialized() {
     this.events.emit('panel-initialized');
   }